Upgrading the Force
The year 1900 was notable for the watch force on at least two accounts. First, Congress responded to the Chief of Engineers by authorizing four more night watchman positions and a sergeant for the force.  The night jobs were filled with some difficulty: the higher pay of $720 per annum versus $660 for the day watchmen did not prevent several of the latter from declining invitations for them. The sergeant's post, paying $900, was taken by Thomas F. O'Neill, the night watchman at Judiciary Park. O'Neill, born in Dublin in 1847, had served with the 7th U.S. Cavalry and was in Maj. Marcus A. Reno's command at Little Big Horn on June 25, 1876. Leaving the Army in 1882, he moved to Washington and joined the park watch in 1890. His promotion to become its first ranking officer suggests that he performed well. Sergeant O'Neill remained on duty until his death on March 22, 1914. He was buried in Arlington National Cemetery. 
The other significant event of 1900 was the uniforming of the force. Col. Theodore A. Bingham, then officer in charge of Public Buildings and Grounds, took a close personal interest in this matter. The previous October he had written his friend John B. Jackson, first secretary of the American Embassy in Berlin, to request a picture of a German forester's uniform and a sample of "real 'Tyrolean loden'" that could be copied for his park watchmen.  Jackson complied via diplomatic pouch. Bingham then negotiated with Saks and Company in Washington and the New York Clothing House in Baltimore, finally selecting the latter as best able to meet his exacting specifications for design, material, color, buttons, and badges. ("[A]lthough they are undoubtedly of Hebraic descent they have on the whole treated me very squarely," he wrote a Cleveland official seeking to uniform that city's park watchmen.) 
Modeled after the German foresters' dress, the uniform was dark green with a tan straw helmet for summer wear. The jacket was three-quarter length with a half-belt on the back panel and five brown buttons. Black braid stripes lined the outer seams of the trousers. Sergeant O'Neill's jacket also had black braid chevrons pointed down on the sleeves. The complete uniform, issued at midyear, cost each man $17.75 (with no allowance); the government furnished only the cap ornament, badge, and club. 
Unfortunately, Colonel Bingham's carefully selected loden green faded rapidly, causing his successor, Col. Thomas W. Symonds, to change the uniform after only three years. The 1903 model was dark blue with a gray felt helmet and brass buttons. The still-unofficial "park police" designation received further sanction at this time: "U.S. Park Police" appeared on the helmet badge, the buttons had "U.S." in the center encircled by "Park" above and "Police" below, and there were "U.S.P.P." collar ornaments.  The men still had to purchase the uniforms and the revolvers they now carried at their own expense; the government did not provide or bear the cost of these items until 1912.
The annual reports of the Chief of Engineers during this period regularly urged more men, more pay, and higher status for the watch force. According to the 1902 report,
This compared to $75 per month for the lowest grade of Metropolitan policeman, rising to $90 after five or six years. The report recommended that all fines and forfeitures from cases brought by watchmen be paid into a separate retirement and disability fund for them rather than going into the Metropolitan Police fund that did not benefit them. That recommendation was not immediately adopted, but the watchmen were given "free medical attendance just like the regular police of the city" that year. 
The report noted that the watch force, then consisting of a sergeant and 29 men, were "drilled in simple movements once a week, and [were] occasionally reviewed by the officer in charge." Colonel Bingham told the Civil Service Commission that year that he wanted "exceptionally good men" because of the small size of the force. They needed to be no more than 58 years old, no less than five feet six inches tall and 165 pounds in weight, in good physical condition, and capable of writing legibly to make out reports. Long military service, preferably as a noncommissioned officer, was desirable "for discipline, punctuality, and cleanliness." 
The Chief of Engineers' report for 1903 described the force as still undermanned. Many parks had only one watchman patrolling for only eight hours. As a result, "During the off hours park loafers [took] advantage of the absence of the watchmen to do about as they please and subject respectable people to annoyance." The force needed to be enlarged further and to have its official designation changed to reflect its true nature:
The 1907 report repeated the call for redesignation, requested more money for the bicycles then in use by the men, and asked for a second sergeant at $1,050 per annum:
Through 1908, Congress continued to specify the park duty stations of watchmen in its appropriations acts. In that year the Chief of Engineers asked for an end to the practice.  Congress complied, enabling flexibility in assigning men where they were most needed.
"The general conduct of the men was good, and but few of them were reported for infractions of the regulations," the Chief of Engineers reported in 1912. "The watchmen enforced the police and park regulations in the parks, public travel on the park roads was regulated by them, fast driving kept down, the lawns, shrubbery, trees, and flower beds were protected from injury, women and children were protected from annoyances, known vagrants and loafers were kept out of the parks, all persons under the influence of liquor were ejected, and rowdyism and disorder were prevented."  When a watchman did go wrong, he could be punished by a loss of annual leave. 
The emphasis on hiring military veterans up to the age of 58 meant that youthful vigor was still not characteristic of the force. In 1914 a bill backed by Public Buildings and Grounds was introduced in Congress to replace the 28 Metropolitan policemen then detailed to the White House with park policemen. Joseph P. Tumulty, secretary to President Woodrow Wilson, protested to Col. William W. Harts, in charge of Public Buildings and Grounds: "As a rule the park policemen assigned to duty in the Federal parks throughout the District are too old for duty at the White House, where none but alert, robust, and active men should serve in such a capacity." Harts defended the proposed extension of his office's responsibility: "I am confident that there need be no trouble about the selection of alert, intelligent and physically well qualified men for these positions should I be required to undertake this duty. Such men . . . would not necessarily be selected from the present park police force." Unpersuaded and not wishing to have to train new men for White House duty, Tumulty conveyed his opposition to the Secretary of War, whose office thereupon recommended against the bill, insuring its demise. 
The park watchmen did assume some additional responsibilities in 1915 when they were posted at the Easter egg rolling festivities on the White House grounds and the annual review of the High School Cadets -- events previously covered by the Metropolitan Police. That year, too, the Chief of Engineers first sought to bring the force into the motor age:
To handle the problem, he requested appropriations for a motorcycle. 
By 1917, two years later, the force had two motorcycles -- one assigned to the first sergeant, the other to a private. The first sergeant, another sergeant, and 43 privates (two of whom were acting sergeants without additional pay) made up its strength. Forty-one of the privates were equipped with bicycles. The force was now under the direct supervision of an Army officer detailed as an assistant to the officer in charge of Public Buildings and Grounds. The Chief of Engineers portrayed the force as an elite unit:
During the fiscal year ending in June 1917, the force handled 717 offenses. The most common charge (315) was drunkenness, for which the most common punishment (99) was the workhouse. There were few serious offenses, the worst being six cases of assault and one of robbery. Other cases included five instances of insanity (the subjects were sent to St. Elizabeth's), five charges of fornication (resulting in three fines and two workhouse sentences), and 15 collisions. 
The women's suffrage movement became increasingly vocal during this period, involving the park policemen on at least one occasion in 1918. Twenty-five of the force were called upon to arrest about 50 women for climbing on the Lafayette statue in Lafayette Park and for holding a meeting there in violation of Section 4, Article VII of Rules and Regulations of the U.S. Parks and Reservations, which prohibited "the holding of any meeting" except religious meetings for which the Chief of Engineers had granted permission. According to their supervising Army officer, "The members of the Park Police conducted themselves with restraint and courtesy towards these women known as Suffragists."
In 1919 the force acquired a major new responsibility and finally achieved its long-sought official designation. The new responsibility came that September when the administration of Rock Creek Park was transferred from its own board of control to Public Buildings and Grounds. The Metropolitan Police had patrolled Rock Creek Park, by far the largest park in Washington, since 1894; henceforth the park police would have this duty. Soon afterward, by an act of Congress approved December 5, 1919, the force was legally titled "United States Park Police." 
The enhanced status and responsibility were accompanied by greater strength and equipment. As of mid-1921 the force had a lieutenant, three sergeants, and 53 privates. Two of the sergeants and seven privates rode motorcycles; the lieutenant, the third sergeant, and 45 privates had bicycles; and the remaining private was horse-mounted.  With the addition of Rock Creek Park and the increased motorcycle capability, Park Police arrests soared from the 717 reported in fiscal year 1917 to 1,829 in fiscal 1920.
The composition of offenses changed dramatically in those three years. There were only half as many arrests for drunkenness (154) but 16 times as many for fornication (81). (No doubt this shift reflected a change of police emphasis to combat what was becoming a more flagrant situation in the "roaring 20s" rather than a decline in public intoxication.) By far the most arrests were now for "violation of traffic regulations" (439) and "violation of police regulations" (458) as the roads and traffic under Park Police jurisdiction increased and as miscellaneous offenses were lumped together in record-keeping. 
Of course, members of the force sometimes failed to meet the high standards expected of them and had to be punished for various infractions. The record of disciplinary actions during 1921-1922 is illustrative. Pvt. M. W. Carlson forfeited one day of annual leave "for sitting on a Bench in the Park while on Duty and in full Uniform." Pvt. William D. Hennessy got the same punishment "for engaging in an unofficial conversation with a citizen for a period of (25) minutes." Pvt. Thomas Bell was suspended for a day "for being in a Government Building for 30 minutes without authority." Pvt. Jeffrey Connell drew a two-day suspension "for engaging in an altercation with another man while in Uniform to the Disgrace of the U.S. Park Police"; soon afterward he was temporarily reduced to the grade of U.S. Watchman (a guard position) "for general inefficiency." Sgt. Carroll T. Gillespie suffered the greatest loss, being reduced to private "for signing [a] petition and general unsatisfactory work." 
Notwithstanding its increased strength, the force was still insufficient to meet the demands upon it, particularly those posed by Rock Creek Park. Lt. Col. Clarence O. Sherrill, who took charge of Public Buildings and Grounds in 1921, remarked on the problem before the House Committee on Public Buildings and Grounds a year later:
Legislation enacted May 27, 1924, specified the organization and entitlements of the force at that time and its salaries as of July 1:
The sergeants' and privates' pay was $100 less than that of their Metropolitan Police counterparts, but the latter had to pay for their uniforms. Colonel Sherrill thought the clothing allowance for his men "a very advantageous arrangement, because in that way I am able to see that they are neatly uniformed. If you will see the park policemen with their long stockings and knickerbockers, mounted on motorcycles, you will agree that they are a very likely lot of men." 
In February 1925, Congress abolished the Public Buildings and Grounds office under the Army's Chief of Engineers and assigned its responsibilities to a new Office of Public Buildings and Public Parks of the National Capital, an independent agency reporting directly to the President.  Colonel Sherrill became director of the successor agency and carried on with the same staff, so the reorganization had little practical effect on the parks and their police force. Upon Sherrill's retirement that December, Maj. Ulysses S. Grant III, grandson of the Civil War general and 18th President, took his place and held it nearly to the end of the agency's existence in 1933.
Major Grant's annual report for 1926 revealed further growth in the U.S. Park Police to 61 privates. The lieutenant was furnished with a "two passenger vehicle," 20 of the men had motorcycles, and the rest got about on bicycles.  Perhaps the lieutenant's vehicle was a motorcycle with sidecar, for the Park Police acquired their first automobile in 1929 according to Grant's testimony before the House Appropriations Committee in 1932. By the latter date the force had six cars, all Fords: three runabouts, two sedans, and a touring car. 
In 1931 Grant reported that the force had expanded its modus operandi in another direction:
When parks were still relatively safe at night and air conditioning was unknown, Washington's downtown residents sometimes slept in the parks during heat waves. The vagrancy laws prohibited such activity, but they were not enforced at such times against "respectable" citizens. On the night of July 26, 1931, for example, more than 200 people from nearby rooming houses slept in Judiciary Square. Lest the privilege be abused, the Park Police awoke them between 7:00 and 7:30, ostensibly as a service. Patrick J. Carroll, the acting chief, told the Evening Star: "The park police realize that most of the people sleeping in the parks are employed and are there to escape the heat. The park police are doing everything possible to see that these people are well taken care of. We don't want them to be late for work, so the men awaken them in time for breakfast." 
The following year the Park Police received their greatest additional responsibility since Rock Creek Park and their first outside Washington. When the Mount Vernon Memorial Highway on the Virginia shore of the Potomac opened early in 1932 for the bicentennial of George Washington's birth, 12 Park Police officers were assigned to patrol it.  This route from Arlington Memorial Bridge down to Mount Vernon was the first development of the George Washington Memorial Parkway, whose landscaped roadways would ultimately extend upriver to the Capital Beltway in Virginia and from Chain Bridge nearly to Great Falls in Maryland. As will be seen, the assumption of this and subsequent duties beyond the District of Columbia would help the Park Police fend off later threats to their independence.
On June 10, 1933, President Franklin D. Roosevelt signed an executive order abolishing the Office of Public Buildings and Public Parks of the National Capital and assigning its functions to the National Park Service effective August 10. The same order gave the NPS the historic battlefields and fortifications then managed as national parks and monuments by the War Department and the national monuments within national forests under the Department of Agriculture. 
The National Park Service, a bureau of the Department of the Interior, had been created by Congress in 1916 to manage the national parks and monuments then under Interior and "such other national parks and reservations of like character as may be hereafter created by Congress."  The 1933 executive order was the culmination of a long campaign by its aggressive leadership to expand its scope beyond the western parks and monuments that constituted its primary responsibilities to that time. With the prominent memorials and parklands of the nation's capital in its custody, the NPS was assured of high visibility and enhanced public and political support.
Washington's parks (previously under Interior from 1849 to 1867) and the U.S. Park Police were now assigned to an NPS office with the administrative designation of National Capital Parks. But the reorganization had no immediate, dramatic effects on them. The police chief at the time, Capt. Patrick J. Carroll, and his men remained on duty, as did most of the civilian staff from the former Office of Public Buildings and Public Parks of the National Capital.  There was some infusion of personnel from elsewhere in the NPS: C. Marshall Finnan came from the superintendency of Mesa Verde National Park to superintend National Capital Parks, and other wearers of the NPS green followed. Because the NPS had no other police force, there was no movement of policemen as a result of the reorganization. The U.S. Park Police would not experience significant consequences from its inclusion in the National Park Service until the 1960s and 1970s, when men from outside the force were brought in to head it and when some of its men were assigned elsewhere in the national park system.