Civil War Defenses of Washington
Historic Resource Study
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War Clouds on the Horizon

As war clouds began to appear, Washington, D.C. was in the midst of the conflict. The city was, for all practical purposes, southern, and many of its citizens had strong southern inclinations. In addition, the Capital was sandwiched between two slave states, both south of the Mason & Dixon Line. Few government troops were in the vicinity and of those that were, some of the officers and men chose to join the new Confederate armed forces and headed south for that purpose. Thus, until more troops arrived, Washington, D.C. was a community under siege. [1]

Brevet Lieutenant General Winfield Scott, commanding general of the army, was not particularly concerned over the capital's safety. Regardless, on January 2, Scott appointed Colonel Charles P. Stone, the Inspector General of the District of Columbia. Stone, who had served under the general during the Mexican War, would be responsible for the defense of the city and he had a plan acceptable to Scott. [2]

Stone speedily undertook his duties, including organizing and drilling the District militia. Scott, who didn't trust the district militia, ordered the Army Regulars to Washington. Regular Army units of all arms–infantry, cavalry and artillery as well as Engineer Sappers and Miners– responded to the call and on February 12, the day before the electoral college met, they were guarding the principal government buildings–White House, Treasury, Capitol, Patent Office and Post Office. The next day they kept an unruly mob, composed of Maryland, District of Columbia and Virginia southern sympathizers, from disrupting the deliberations of the electoral college or creating mischief in general. [3]

The president-elect, Abraham Lincoln, arrived in Washington at 6 a.m. on February 23, and traveled to the Willard Hotel, his temporary residence. Lincoln's trip from Illinois was not uneventful, he was secreted through Baltimore, where the train had to slow down and switch tracks, before continuing on to the capital. Upon his arrival, the government finalized its security plans for the imminent inauguration, on March 4, 1861. [4]

Inaugural day arrived and many were apprehensive. Riflemen were posted along the parade route and in the Capitol. Artillery, cavalry and various other military units took station at a variety of points along the route, but out of the citizens' view, to counter any possible mob violence. Unbeknownst to most of the spectators, local militiamen protected the inaugural platform. The inaugural activities concluded without any problems! [5]

Stone's plan for the defense of the city did not include any fortifications except barricades. The plan even excluded Fort Washington, Maryland. The plan, however, did establish "strongpoint" centers at City Hall hill, comprising in its area the General Post Office and the Patent Office, at the Capitol, and Executive Square, which included the White House and the Treasury, State, Navy and War buildings. The Treasury Building would be the enceinte, the last-ditch position, for a final fight. Thankfully, circumstances never necessitated a retreat to these positions. [6]

The inauguration had come and gone but the fear for the Capital's safety continued due to military reverses nearby and the lack of troops in the city. Fort Sumter, in Charleston Harbor, surrendered on April 14, 1861. The burned-out Harpers Ferry armory fell to the rebels on April 19, and the Confederates occupied the destroyed Gosport Navy Yard on April 21. In addition, riots broke out in Baltimore on April 19, 1861, between pro-Confederate and pro-Union citizens. Among other results, the riots cut-off railroad communication with the North.

President Lincoln, on April 1, 1861, had requested Winfield Scott to inform him daily of the military situation throughout the country and the news was not pleasant. On April 15, Lincoln declared that "an insurrection existed," called for seventy-five thousand troops and convened Congress in a special session to begin on July 4. The call for troops caused bad feeling in some southern-leaning states such as Missouri, Kentucky, Maryland, North Carolina and Virginia. The Virginia State Convention passed "an ordinance of secession" and ordered a May 23 public referendum on it. The Army countered by creating the Department of Washington, encompassing the District of Columbia and the State of Maryland, under the command of Brevet Colonel Charles F. Smith. But, when would more troops arrive to enable control of the department? [7]

Some Pennsylvania militia and regulars from Minnesota arrived in the capital on April 18, to join approximately 600 District of Columbia militia, 200 U.S. Marines and about 600 regulars. The Sixth Massachusetts Infantry Regiment arrived the next day, after experiencing problems and violence in Baltimore. Since some Baltimore citizens destroyed that city's railroad bridges during the riots, land transportation to Washington was stopped. The U.S. Navy offered an alternative route to the capital. [8]

Captain Samuel F. Du Pont, Philadelphia Navy Yard Commandant, initiated a maritime rescue operation. The steamer Boston and railroad ferryboat Maryland would transport troops from Philadelphia and Perryville, where the Susquehanna River flows into the Chesapeake, to Annapolis, Maryland. From Annapolis, the railroad would transport the men to Washington. On April 21, word reached Washington that the First Rhode Island Infantry Regiment, the Seventh New York Infantry Regiment, and a force of Massachusetts troops under the command of Major General Benjamin Butler, were offshore at Annapolis. These troops would land and rebuild the railroad line to proceed to Washington. The Seventh New York Infantry Regiment arrived in Washington on the 25th and the First Rhode Island Infantry Regiment began arriving on the 26th. Numerous other units from a variety of states soon reached Washington also and the citizenry's siege mentality dissipated. [9]

The Navy also had other duties. President Lincoln proclaimed a naval blockade of the Confederacy on April 19 and the U.S. Navy channeled much of its efforts in that direction. But, the Navy, like the Marines, also took an active part in the defense of the Capital. Lincoln visited the Washington Navy Yard on April 2 to discuss its defense with the commandant, Commander John A. Dahlgren. Afterwards, he periodically conferred with Dahlgren on the defense of Washington, including guarding river approaches and safe-guarding the Anacostia Bridge. On April 21, Dahlgren obtained and outfitted four steamers at the Washington Navy Yard for the defense of Washington. The USS Pawnee, which had been at the Gosport Navy Yard before yard was destroyed and capitulated, arrived in Washington on the 23rd to assist in the capital's defense. The day before, Commander James H. Ward, for whom a fort in the Defenses of Washington would later be named, suggested the organization of a "flying flotilla" for the defense of the entire Chesapeake Bay area, including the Capital. In May, Ward arrived at the Washington Navy Yard with the USS Thomas Freeborn and two other vessels in tow to command the "Potomac Flotilla." [10]

Within five days of the Seventh New York Infantry Regiment's arrival in the Union capital, 7,500 volunteers were quartered in the city and by the end of the month, the number had grown to nearly 11,000. Some resided in the Treasury Building, Patent Office, City Hall, Navy Yard and even in the Capitol. As more and more men arrived, troops encamped and drilled wherever unused land was found and supply centers sprang up in a variety of locations. By August, most of the troops that had arrived in Washington were located outside the urban limits of Washington. [11]

In the meantime, important activities were occurring around the District of Columbia. Ben Butler and his forces had stayed in Maryland after their arrival in Annapolis and attempted to insure that state would remain in the Union. On the evening of May 13, Butler arrived in Baltimore with about 1,000 men, including some artillery men with guns. Butler quickly moved his men to occupy Federal Hill, a prominence from which the artillery could shell almost any downtown area, and, as the authors of Baltimore During the Civil War wrote, "armed resistance in the city came to an end." Attention turned to Virginia where Confederate flags were visible from highpoints in Washington, rebel troops' campfires blazed at night, and the citizenry would vote on secession soon, on May 23. Given the large number of troops now in Washington, only a few feared these events in Virginia. Colonel J.F.K. Mansfield, the then commander of the Department of Washington, however, argued for the occupation of Northern Virginia to preclude the possibility of rebels mounting artillery on its heights and shelling government buildings in the capital. He also urged the occupation of Alexandria to insure navigation on the Potomac River and the erection of fortifications on the Virginia side to protect the southern terminus of the Chain and Long Bridges and the Aqueduct. His superiors approved these recommendations but implementation was delayed until after the Virginia citizenry's popular referendum on secession. [12]

On May 23, 1861, the public referendum in the State of Virginia held on the Ordinance of Secession was three to one in favor of leaving the Union. Many in Washington had been sure that the vote would go that way but waited to make sure before launching a military force into Northern Virginia. After months of non-activity in the area, military movements began. [13] The May 25, 1861 issue of The New York Herald included the following article, "THE INSURRECTION. ADVANCE OF THE FEDERAL TROOPS INTO VIRGINIA, WASHINGTON, May 24, 1861":

There can be no more complaints of inactivity of the government. The forward march movement into Virginia, indicated in my despatches last night, took place at the precise time this morning that I named, but in much more imposing and powerful numbers.

About ten o'clock last night four companies of picked men moved over the Long Bridge, as an advance guard. They were sent to reconnoitre, and if assailed were ordered to signal, when they would have been reinforced by a corps of regular infantry and a battery.

At twelve o'clock Colonel Ellsworth's regiment of Zouaves embarked in steamers from the Navy Yard for Alexandria, and must have reached there about one o'clock this morning. They landed under the cover of the Pawnee's guns. An attack would have been signalized. No attack was made.

At twelve o'clock the infantry regiment, artillery and cavalry corps began to muster and assume marching order. As fast as the several regiments were ready they proceeded to the Long Bridge, those in Washington being directed to take that route.

The troops quartered at Georgetown, the Sixty-ninth, Fifth, Eighth and Twenty-eighth New York regiments, proceeded across what is known as the chain bridge, above the mouth of the Potomac Aqueduct, under the command of General McDowell. They took possession of the heights in that direction.

The imposing scene was at the Long Bridge, where the main body of the troops crossed. Eight thousand infantry, two regular cavalry companies and two sections of Sherman's artillery battalion, consisting of two batteries, were in line this side of the Long Bridge at two o'clock.

The Twelfth (New York) was the first on the ground. The army crossed the bridge in the following order:

— Twelfth regiment, New York.

— Twenty-fifth regiment, New York.

— First regiment, Michigan.

— First, Second, Third and Fourth, New Jersey, in the order named.

— Two regular cavalry corps, of eighty men each, and Sherman's two batteries.

— Next and last came the New York Seventh, the liveliest party, and with more men than any other regiment. They seemed delighted at the idea that they were to have a show at something that looked like service before returning home.

— Following them was a long train of wagons filled with wheelbarrows, shovels, &c.

Altogether there were at least thirteen thousand troops in the advancing army. This includes the Zouaves who went by steamer, the forces that moved from Georgetown, as well as the main body that proceeded over the Long Bridge.

General Mansfield commanded the movement of the troops until the last corps left the district. The first regiment of the main body that crossed the Long Bridge started at twenty minutes past two, and the last corps left the district at about a quarter to four o'clock.

At four o'clock Major General Sandford and staff left Willard's, and proceeded to Virginia to take command of the advancing forces. He informed me that he should establish his headquarters on Arlington Heights, and should take possession of the Arlington mansion.

Two thousand troops, the New York Zouaves and New York Twelfth, are to occupy Alexandria; the remainder the heights by regiments from the chain bridge to Alexandria.

General Mansfield took the greatest care to instruct the troops just before entering the bridge to take the route step-that is, to avoid marching together, as the solid step together might injure the bridge. . . .

The sun of the 24th of May has risen and exposed to our gratifying gaze the Stars and Stripes floating over Alexandria, where the secession flag has been haunting the sight for weeks past. Truly the past has been a great night's work for the Union. Secession is suddenly doomed, and nothing but an ignominious doom awaits the leading traitors in this great wrong against popular government and free institutions." [14]

For the most part, the occupation of Northern Virginia was peaceful except in Alexandria. There, Colonel Elmer E. Ellsworth, commander of the New York Fire Zouaves (Eleventh New York Volunteer Infantry Regiment) and a friend of President Lincoln, ascended the Marshall House to remove the Confederate flag flying above it. As he descended the steps, with the flag, James Jackson, the proprietor, shot and killed Ellsworth with a shotgun making him one of the first Union martyrs. [15]

The Defenses of Washington

One author wrote, "Accompanying the troops was an ample supply of entrenching tools, and by daylight of the 24th ground had been broken for two forts–Fort Runyon to guard the head of the Long Bridge, and Fort Corcoran to guard the head of the Aqueduct." [16] Engineer troops and officers accompanied the force that night to specifically prepare defenses. Engineer officers such as Barton S. Alexander, Horatio G. Wright, Frederick E. Prime and Daniel P. Woodbury, under Major John G. Barnard's leadership, set about laying out the fortifications and supervising their erection. [Cooling, Symbol, 37] Barnard reported that:

"As tetes-de-pont to the Long Bridge and Aqueduct, Forts Runyon and Corcoran, the sites of which had been previously reconnoitered under my directions, were commenced at daylight on the morning, of the 24th. The same day a reconnaissance was made in the vicinity of Alexandria by Captain Wright, Engineers (now, Major-General U. S. Volunteers), and Fort Ellsworth, to secure our possession of that city, was commenced. A couple of weeks later, I laid out Fort Albany (intended to command the Columbia and the Aqueduct and Alexandria roads, and to give greater security to our debouche' by the long Bridge), which was commenced under Captain Blunt, Engineers.

These works were all of considerable magnitude (Fort Runyon having a perimeter of 1,500 yards). They were not entirely completed, though very nearly so, and quite defensible, at the date of the advance of the army under Gen. McDowell (July 16).

I give this brief account of these preliminary works, because they formed the initiation of the system of "Defences of Washington." [17]

Elsewhere, Barnard explained:

"Previous to this movement the army of Washington, yet weak in numbers and imperfectly organized. under General Mansfield, had crossed the Potomac and occupied the south bank from opposite Georgetown to Alexandria. The first operations of field engineering were, necessarily, the securing of our debouches to the other shore and establishing of a strong point to strengthen our hold of Alexandria. The works required for these limited objects (though being really little towards constructing a defensive line) were nevertheless, considering the small number of troops available, arduous undertakings. Fort Corcoran, with its auxiliary works, Forts Bennett and Haggerty, and the block-houses and infantry parapets around the head of the Aqueduct, Forts Runyon, Jackson, and Albany (covering our debouches from the Long Bridge), and Fort Ellsworth, on Shooter's Hill, Alexandria, were mostly works of large dimensions. During the seven weeks which elapsed between the crossing of the Potomac and the advance of General McDowell's army the engineer officers under my command were so exclusively occupied with these works (all of which were nearly completed at the latter date), to make impracticable the more general reconnaissances and studies necessary for locating a line of defensive works around the city and preparing plans and estimates of the same.

The works just mentioned on the south of the Potomac, necessary for the operations of an army on that shore, were far from constituting a defensive system which would enable an inferior force to hold the long line from Alexandria to Georgetown or even to secure the heights of Arlington." [18]

On May 27, Scott established a new department that comprised all of the State of Virginia east of the Allegheny Mountains and north of the James River, except for Fort Monroe and sixty miles around it. It was named the Department of Northeast Virginia and was commanded by Brig. Gen. Irvin McDowell, who established his headquarters at Arlington House (Custis-Lee Mansion), owned by Robert E. Lee. The troops in this command faced guerilla activity and minor raids and skirmished with rebels in a variety of locations. These events never caused much trouble but they were a nuisance and kept the green Union troops forever on alert. [19]

While the Union concentrated forces behind the new defenses in Northern Virginia, the Confederates amassed troops to protect the railroad center of Manassas Junction. Many at that time thought that one main battle would decide the conflict between North and South. Those in the North clamored for an immediate confrontation before the South could mobilize, train and concentrate troops. In addition, many of the Union troops in the Washington had short terms of service, many for 90 days, so why not use them before they returned home. McDowell moved his troops out toward Manassas on July 16, pursuant to the President's orders. He had organized his army into brigades in five divisions commanded by Colonels Dixon Miles, David Hunter and Samuel P. Heintzelman and Brigadier Generals Theodore Runyon and Daniel Tyler. This Union force clashed with Confederate forces under the command of Brigadier Generals P.G.T. Beauregard and Joseph E. Johnston at Manassas on July 21, 1861. [20]

In the First Battle of Manassas, the Union army, at first, appeared to be winning, forcing the Confederate army to retreat. But, later in the day, the rebels made a stand on Henry House Hill and then counterattacked, forcing the Union army into retreat that ballooned into a rout. Besides the troops and their supply wagons, many civilian observers trekked to Manassas in their horse and buggies, and picnic lunches, to see what battle entailed. When the fighting turned into a rout, civilians became entangled with the Union army in its flight back to Washington, aiding and abetting the rout. [21]

Fear returned to the capital. Now that the Confederates had won the first major land battle of the war and the Union army was disorganized and in rout, what would happen. Would the rebels capture Washington? Would they destroy the city? Would they arrest and execute loyal Unionists? Thankfully, in the next few days the confederate army realized that it also had become disorganized by the fighting that occurred at Manassas and could not, immediately, undertake an attack on the Union capital. [22]

This fear of Confederate capture was the impetus for designing and constructing a system of fortifications to encircle and defend Washington, D.C. In the wake of defeat, the Union called Major General George B. McClellan, who had won some battles in West Virginia, to Washington and on July 27, only a few days after the defeat at Manassas, gave him command of the troops in the vicinity of Washington, D.C. Nicknamed "Little Mac," McClellan, a West Point graduate, had served in the Regular Army from 1846 until 1857, when he resigned his commission and took a position with the railroads. For most of his army service, from 1846 to 1855, he had been an Army Engineer and, therefore, had an appreciation for fortifications and their use. Thus, in addition to reorganizing the army and formulating new plans to fight the enemy, McClellan ordered the erection of a system of fortifications. [23]

Although there are no written orders or instructions from McClellan describing exactly what he wanted done on the defenses of Washington, he did declare: "When I assumed command of the Army of the Potomac I found Maj. J. G. Barnard, . . . occupying the position of chief engineer of that army. I continued him in the same office, and at once gave the necessary instructions for the completion of the defenses of the capital . . ." And Barnard wrote: "I would add that to the great importance attached to these works by the commanding general [McClellan] . . . to his valuable suggestions and prompt and cordial co-operation, the present state of efficiency of the defenses of Washington is in no small degree due." [24]

When McClellan "assumed command in Washington, on the 27th of July, 1861," he found that:

"In no quarter were the dispositions for defense such as to offer a vigorous resistance to a respectable body of the enemy, either in the position and numbers of the troops or the number and character of the defensive works. Earthworks, in the nature of tetes-de-pont, looked upon the approaches to the Georgetown Aqueduct and Ferry, the Long Bridge, and Alexandria, by the Little River turnpike, and some simple defensive arrangements were made at

the Chain Bridge. With the latter exception not a single defensive work had been commenced on the Maryland side. There was nothing to prevent the enemy shelling the city from heights within easy range, which could be occupied by a hostile column almost without resistance." [25]

So, Barnard reported:

"On the retreat of our army such was our situation. Upon an inferior and demoralized force, in presence of a victorious and superior enemy, was imposed the duty of holding this line and defending the city of Washington against attacks from columns of the enemy who might cross the Potomac (as was then deemed probable) above or below.

Undecided before as to the necessity, or at least the policy, of surrounding Washington by a chain of fortifications, the situation left no longer room to doubt. With our army too demoralized and too weak in numbers to act effectually in the open field against the invading enemy, nothing but the protection of defensive works could give any degree of security. Indeed, it is probable that we owe our exemption from the real disaster which might have flowed from the defeat of Bull Run–the loss to the enemy of the real fruits of his victory–to the works previously built (already mentioned), and an exaggerated idea on his part of their efficiency as a defensive line.

The situation was such as to admit of no elaborate plans nor previouslyprepared estimates. Defensive arrangements were improvised and works commenced as speedily as possible where most needed. A belt of woods was felled through the forest in front of Arlington and half-sunk batteries prepared along the ridge in front of Fort Corcoran and at suitable points near Fort Albany, and a battery of two rifled 42-pounders (Battery Cameron)was established on the heights near the distributing reservoir above Georgetown to sweep the approaches to Fort Corcoran.

Simultaneously a chain of lunettes (Forts De Kalb, Woodbury, Cass, Tillinghast, and Craig) was commenced, connecting Fort Corcoran and the Potomac on the right with Fort Albany on the left, and forming a continuous defensive line in advance of the heights of Arlington. The wooded ridge which lies north of and parallel to the lower course of Four Mile Run offered a position from which the city, the Long Bridge, and the plateau in advance of it could be overlooked and cannonaded. While our external line was so incomplete, it was important to exclude the enemy from its possession. Access to it was made difficult by felling the forest which covered it (about 200 acres), and the large lunette (Fort Scott) was commenced as soon as the site could be fixed (about the middle of August). The subsequent establishment of our defensive line in advance throws this work into the same category with Forts Corcoran, Albany, Runyon, &c., as an interior work, or second line, but it is nevertheless an important work, as, taken in connection with Forts Richardson, Craig, &c., it completes a defensive line for Washington independent of the extension to Alexandria.

The defense of Alexandria and its connection with that of Washington was a subject of anxious study. The exigency demanding immediate measures, the first idea was naturally to make use of Fort Ellsworth as one point of our line, and to connect it with Fort Scott by an intermediate work on Mount Ida. An extended study of the topography for several miles in advance showed that such a line would be almost indefensible. Not only would the works themselves be commanded by surrounding heights, but the troops which should support them would be restricted to a narrow space, in which they would be overlooked and harassed by the enemy's distant fire. The occupation of the heights a mile in advance of Fort Ellsworth, upon which the Episcopal Seminary is situated, seemed absolutely necessary. The topography proved admirably adapted to the formation of such a line, and Forts Worth and Ward were commenced about the 1st of September, and the line continued simultaneously by Forts Blenker and Richardson to connect with Forts Albany and Craig. Somewhat later the work intermediate between Blenker and Richardson–filling up the gap and having an important bearing upon the approaches to Forts Ward and Blenker and the valley of Four Mile Run–was commenced.

The heights south of Hunting Creek, overlooking Alexandria and commanding Fort Ellsworth, had been always a subject of anxiety. The securing to our own possession the Seminary Heights, which commanded them, diminished materially the danger. As soon, however, as a sufficient force could be detached to occupy those heights and protect the construction of the work it was undertaken, and the large work (Fort Lyon) laid out and commenced about the middle of September.

Previous to the movement of the army defensive measures had been taken at the Chain Bridge, consisting of a barricade (bullet proof, and so arranged as to be thrown down at will) across the bridge, immediately over the first pier from the Virginia side, with a movable staircase to the flats below, by which the defenders could retreat, leaving the bridge open to the fire of a battery of two field guns immediately at its Maryland end, and a battery on the bluff above (Battery Martin Scott) of one 8-inch sea-coast howitzer and two 32-pounders. As even this last battery was commanded by heights on the Virginia side, it was deemed proper, after the return of the army, to erect another battery (Battery Vermont) at a higher point, which should command the Virginia Heights and at the same time sweep the approaches of the enemy along the Maryland shore of the Potomac.

During the months of May and June the country between the Potomac and the Anacostia had been examined mainly with the view of obtaining knowledge of the roads and defensive character of the ground, not in reference to locating field defenses. At the period now in question there was apprehension that the enemy might cross the Potomac and attack on this side. Of course what could be done to meet the emergency could only be done without that deliberate study by which a complete defensive line would best be established. The first directions given to our labors were to secure the roads, not merely as the beaten highways of travel from the country to the city, but also as in general occupying the best ground for an enemy's approach.

Thus the sites of Forts Pennsylvania, Massachusetts, Slocum, Totten, Bunker Hill, Saratoga, and Lincoln were rapidly chosen, and works commenced simultaneously at the first, second, third, and sixth of these points early in August.. The others were taken up as speedily as the clearing of the woods and the means at our disposal would admit, and the gaps in the line afterwards partially filled up by construction of Fort Gaines, Forts De Russy, Slemmer, and Thayer. The works mentioned are at this date essentially completed and armed, though there is still considerable to do in auxiliary arrangements. Our first ideas as to defensive works beyond the Anacostia contemplated only the fortification of the debouches from the bridges (Navy-Yard Bridge and Benning's Bridge), and the occupation of the heights overlooking the Navy-Yard Bridge. With that object Fort Stanton was commenced early in September. A further examination of the remarkable ridge between the Anacostia and Oxen Run showed clearly that, to protect the navy-yard and arsenal from bombardment, it was necessary to occupy an extent of 6 miles from Berry's place (Fort Greble) to the intersection of the road from Benning's Bridge (Fort Meigs).

Forts Greble and Carroll were commenced in the latter part of September, and Fort Mahan, near Benning's Bridge, about the same time. Forts Greble and Stanton are completed and armed; Forts Mahan and Carroll very nearly so. To fill up intervals or to sweep ravines not seen by the principal works, Forts Meigs, Dupont, Davis, Baker, Good Hope, Battery Ricketts, and Fort Snyder have been commenced, and it is hoped may be so far advanced before the winter sets in as to get them into a defensible condition. The occupation of the Virginia shore at the Chain Bridge was essential to the operations of our army in Virginia. It was only delayed until our force was sufficient to authorize it. General Smith's division crossed the bridge September –, and Forts Ethan Allen and Marcy were immediately commenced and speedily finished.

A few weeks later (September 28) the positions of Upton's and Mun-son's Hills and Taylor's Tavern were occupied and Fort Ramsay commenced on Upton's Hill. The enemy's works on Munson's and the adjacent hill were strengthened and a lunette built near Taylor's Tavern.

Comprised in the foregoing categories there are twenty-three field forts south of the Potomac, fourteen field forts and three batteries between the Potomac and Anacostia, and eleven field forts beyond the Anacostia, making forty-eight field forts in all. These vary in size from Forts Runyon, Lyon, and Marcy, of which the perimeters are 1,500, 937, and 736 yards, down to Forts Bennett, Haggerty, and Saratoga, &c., with perimeters of 146, 128, and 154 yards. The greater portion of them are inclosed works of earth, though many–as Forts Craig, Tillinghast, Scott, &c., south of the Potomac, and Forts Saratoga, Gaines, &c., on the north–are lunettes with stockaded gorges. The armament is mainly made up of 24 and 32 pounders on sea-coast carriages, with a limited proportion of 24-pounder siege guns, rifled Parrott guns, and

guns on field carriages of lighter caliber. The larger of the works are flanked, but the greater number are not, the sites and dimensions not permitting. Magazines are provided for one hundred rounds of ammunition, and many of the works have a considerable extent of bomb-proof shelter, as Forts Lyon, Worth, and Ward, in the bomb-proofs of which probably one-third of the garrison might comfortably sleep and nearly all take temporary shelter. In nearly all the works there are either bomb-proofs like the above, or log barracks, or blockhouses of some kind.

It would be impossible to go into any details about these constructions. I am in hopes ultimately to be able to deposit in the Engineer Office drawings of each work with sufficient detail for most purposes. The accompanying sheets, Nos. 1 and 2, will exhibit the general location and bearings of the works.(*) The tabular statement herewith will show the perimeters, number of guns, amount of garrison, &c.(+)

It should be observed that most of the works south of the Potomac, having been thrown up almost in the face of the enemy, have very light profiles, the object having been to get cover and a defensive work as speedily as possible. The counterscarps of all the works, with few exceptions, are surrounded by abatis.

It is impossible, at present, to indicate the exact extent of forest cut down. (The drawings herewith represent the forest as it existed before the works were commenced.)(++) The woods in advance of Forts Worth, Ward, and Blenker have been felled; all surrounding and between the next work on the right and Fort Richardson; all the wood on the ridge on which is Fort Scott– a square mile probably–in advance of and surrounding Forts Craig, Tillinghast, and Woodbury, besides large areas north of the Potomac, &c. This fallen timber (most of which still lies on the ground.) rendered an enemy's approach to the lines difficult. The sites of Forts Totten, Slocum, Bunker Hill, Meigs, Stanton, and others were entirely wooded, which, in conjunction with the broken character of the ground, has made the selection of sites frequently very embarrassing and the labor of preparing them very great.

The only case in which forts are connected by earthworks is that of Forts Woodbury and De Kalb, between which an infantry parapet is thrown up,

with emplacements for field guns. The construction here was suggested by the fact that this was on one of the most practicable and probable routes of approach for the enemy. Infantry trenches have, however, been constructed around or in advance of other works, either to cover the construction (as at Fort Lyon), or to see ground not seen by the work (as at Forts Totten, Lincoln, Mahan, &c.).

The works I have now described do not constitute a complete defensive system.

We have been obliged to neglect much and even to throw out of consideration important matters. We have been too much hurried to devise a perfect system, and even now are unable to say precisely what and how many additional points should be occupied and what auxiliary arrangements should be made.

It is safe to say that at least two additional works are required to connect Fort Ethan Allen with Fort De Kalb.

The necessity of protecting the Chain Bridge compelled us to throw the left of our northern line several miles in advance of its natural position, as indicated by the topography to the sites of Forts Ripley, Alexander, and Franklin. Between these and Forts Gaines or Pennsylvania one or two intervening works are necessary.

Between Forts Pennsylvania and De Russy at least one additional work is necessary.

Fort Massachusetts is entirely too small for its important position. Auxiliary works are necessary in connection with it.

Small tetes-de-pont are required around the heads of Benning's and the Navy-Yard Bridges.

Between Forts Mahan and Meigs one or more intervening works and between Forts Du Pont and Davis another work of some magnitude are required, the ground along this line not being yet sufficiently known. A glance at the map will show it to be almost a continuous forest. It is not deemed necessary to connect the works by a continuous line of parapet, but the intervening woods should be abatised and open ground traversed by a line of artificial abatis, and infantry parapets, half-sunk batteries, &c., placed so as to protect these obstructions and to see all the irregularities of the ground not now seen from the works. Considerable work is also required in the way of roads, the amount of which I cannot state with any precision. Several miles of roads have actually been made. The works themselves would be very much strengthened by caponieres in the ditches, additional internal block-houses, or defensive barracks, &c.

The aggregate perimeter of all the works is about 15,500 yards, or nearly 9 miles, including the stockaded gorges, which, however, form a small proportion of the whole, requiring, computed according to the rule adopted for the lines of Torres Vedras, 22,674 men (about) for garrisons.

The number of guns, most of which are actually mounted, is about four hundred and eighty, requiring about 7,200 men to furnish three reliefs of gunners. The permanent garrisons need consist of only these gunners, and even in case of attack it will seldom be necessary to keep full garrisons in all the works.

The total garrisons for all the works (one hundred and fifty-two in number) of the lines of Torres Vedras amounted to 34,125 men; and as the total perimeters are nearly proportional to the total garrisons, it appears that the lines about Washington involve a magnitude of work of about two-thirds of that in the three lines of Torres Vedras.

The works themselves, fewer in number, are generally much larger than those of Torres Vedras, and involve, I believe. when the amount of bombproof shelter in ours is considered, more labor per yard of perimeter; but the latter lines involved a greater amount of auxiliary work, such as the scraping of mountain slopes, palisading, abatis, roads, &c., than we have had occasion to make.

The lines of Torres Vedras were armed with five hundred and thirty–four pieces of ordnance (12, 9, or 6 pounders, with a few field howitzers); ours with four hundred and eighty pieces, of which the greater number are 32-pounders on barbette carriages, the rest being 24-pounders on the same carriages, 24-pounder siege guns, 10, 20, and 30 pounder rifled guns (Parrott), with a few field pieces and howitzers. As to number of guns, therefore, our armament approaches to equality with that of the famous lines mentioned; in weight of metal more than doubles it.

The above applies to our works as now nearly completed, and has no reference to the additional works I have elsewhere mentioned as hereafter necessary. It is impossible to give any other statement of actual cost of the works than the total amount expended thus far. The work has been done partly by troops and partly by hired laborers, the works north of the Potomac being mostly done by the latter. The large amount of carpentry in magazine frames and doors and blindages, barrier gates, stockades, block-houses, defensive barracks, &c., has kept a large gang of carpenters all the time at work, and caused a large expenditure for lumber. The entire amount made available by the Department for these works has been $344,053.46, and this will all have been expended (or more) by the end of the present month. This would give an average of a little over $7,000 for each of the forty-eight works; but of course the real cost of them has been very unequal.

The importance of perfect security to the capital of the United States in the present state of affairs can scarcely be overestimated, and these works give a security which mere numbers cannot give, and at not a tithe the expense of defense by troops alone."

Thus following the defeat at First Manassas, gigantic efforts were directed toward designing and erecting a system of fortifications to protect Washington, D.C., the Union's capital. [26]

After deciding that fortifications are necessary, the first thing to do, hopefully by an Army engineer officer, was to select the right location(s). Dennis Hart Mahan, the Military Engineering professor at the U.S. Military Academy at West Point, New York, wrote:

"As a field fort must rely entirely on its own strength, it should be constructed with such care that the enemy will be forced to abandon an attempt to storm it, and be obliged to resort to the method of regular approaches used in the attack of permanent works. To effect this, all the ground around the fort, within range of the cannon, should offer no shelter to the enemy from its fire; th ditches should be flanked throughout; and the relief be so great as to preclude any attempt at scaling the work." [27]

After the Army engineer officer selected the location of the fortification, he next needed to "throw up the work," "layout the work" or profile it. Some authors have described how to throw up a work:

"56. The foregoing chapters contain all that is requisite to determine the plan and relief of field works under all circumstances of variety of ground. To follow a natural order, the next steps will be to describe the manner of laying the work out on the field, which is termed profiling; the distribution of the workmen to excavate the ditch, and form the parapet; and the precautions to be observed in the construction.

57. Poles (Fig. 18,) having been planted at the angles of the work, and the height of the interior crest-marked on them, a line is traced on the ground, with a pick, showing the direction of the interior crests. At suitable distances, say from twenty to thirty yards apart, cords are stretched between two stout pickets, in a direction perpendicular to the line marked out by the pick; these cords should be exactly horizontal. A stout square picket is driven firmly into the ground, where the cord crosses above the pick-line, and a slip of pine, on which the height of the interior crest is marked, is nailed to the picket. The thickness of the parapet is measured on the cord, and a picket driven into the ground to mark the point. The base of the interior slope and tread of the banquette, are set off in a similar manner; and a slip of deal is nailed to each of the pickets. The height of the interior crest, and the tread of the banquette, are easily ascertained, from the position of the cord, and the interior crest; these points having been marked on their respective slips, the outline of the parapet is shown by connecting them by other slips, which are nailed to the uprights; the banquette slope, and exterior slope, will be determined by a similar process.

58. From the profile thus formed perpendicular to the interior crests, the oblique profiles at the angles can readily be set up, by a process which will suggest itself without explanation.

59. Having completed the profiling, the foot of the banquette, and that of the exterior slope, are marked out with the pick, and also the crests of the scarp and counterscarp. All the arrangements preparatory to commencing the excavation are now complete." [28]

"A stick may be cut to measure lines, and stakes will be driven to show the slope and general form of the profile necessary in each particular case. Whatever the form is to be given to a work, it is traced upon the ground by laying off its angles according to the number of their degrees, and its sides are designated by little furrows dug with the mattock or spade along cords stretched in the proper direction. To profile a work is to figure upon the ground its elevation by means of poles and laths nailed together; (Fig. 127.) The officer who directs the work ought to take with him four or five soldiers who carry mattocks, 100 pickets, twenty poles ten or twelve feet long, twenty laths, some camp colors, and a cord 65 feet in length. There ought to be a carpenter, who carries hammer, nails, and a saw.

Field-works necessary or desirable in the operations of an army in the field to strengthen lines of battle, keep open lines of communication, protect bridges from destruction, &c., will generally be constructed under the supervision of engineers. They may have any extent, from a simple redan, or a battery, to a line or several lines of works, some of considerable magnitude, extending over a position of ten or twenty miles." [29]

"To throw up a work, a line is first traced on the ground with a pick, showing the direction of the interior crest: poles having been planted at the angles of the work, with the height of the interior crest marked on them, cords are then stretched at distances of about thirty yards apart, horizontally between two pickets, perpendicular to the lines." [30]

"The proper height of parapet for the work having been determined, (by the process of defilading, if necessary,) the next step is to plant pickets on the faces, flanks, and angles as guides to the workmen in giving it the suitable dimensions and form. Thus, to the magistral line of each face and flank, trace on the ground perpendicularly at intervals, and on these measure, horizontally, the bases of the slopes composing the profile to be employed. At the points thus set out fix poles or laths perpendicularly in the ground, and saw off their tops at the height which the parapet is to have at that particular part; nail laths to the tops of these poles from one to the other across the direction of the intended parapet; and thus there will be obtained an outline of the slopes, or a profile of the parapet.

For the profile at an angle, lay a rope on the ground bisecting that angle, and produce it outwards; drive pickets along this rope at the points where it is intersected by the prolongations of lines joining the bases of the profiles already set up perpendicularly to the adjoining faces, these pickets mark the bases of the profiles at the salient; the laths may then be set up as before.

When the salient angle is 60%%, the breadth of the base of any slope measured on the capital will be equal to twice the breadth of the same slope taken on a line at right angles to the face." [31]

"The work is commenced by marking on the ground the interior crest, the foot of the interior slope, and the banquette, which is done by a little furrow made with a pick moved along cords stretched in the direction of the lines just mentioned; . . ." [32]

Some soldiers, who observed this construction and often actually worked on the fortifications themselves, penned descriptions:

"On the 29th we were engaged in building a fort on the site of our old camp. The fort or earthwork was a very large one with a ditch or moat all round it. This was filled with water. The outside of the forts were sodded. In building these works the engineers first built a light frame of wood the size and shape that it wanted, and when it is fixed to suit them with the necessary angles, etc. the men are put to work with pick and shovel and digging from the outside throw the dirt between the frame work until it is filled up, some of the men being on the pile to spread the dirt. When it has been graded over nicely, it is covered over with sods. The ditch soon fills with water from the many rain storms, and after the Cheaveaux de Frisse that we employed were large branches of trees pinned to the ground, with the brush outward. The ends of the branches were then cut off and sharpened, and it would have bothered man or horse to get over it." [33]

"A line was laid out by our Engineers and we were ordered to fortify our position. Axes and shovels were furnished and we were soon hard at work. To most of us this was an unfamiliar effort but before our service ended it was one in which we were to become proficient. . . . There was a lot of fallen timber that we gathered and placed lengthwise, then dug a trench behind, with the dirt thrown over the logs. The trench was over two feet deep, wide

enough for the line to stand in and with the embankment the total depth was five feet. These works were quite strong and would protect the men against attack, for an ordinary projectile could not go through the embankment." [34]

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Last Updated: 29-Oct-2004