[Note: Post commanders frequently were absent on field or detached Service. At such times the next ranking officer acted as post commander. Acting post commanders are not shown on this list. At other times an officer senior to the post commander served for a short period at the fort and by virtue of superior rank took temporary command of the post until his departure, when the command reverted to the previous incumbent. These officers are not listed either. Brevet (Bvt.) ranks were conferred for gallant or meritorious service. If ordered by proper authority, an officer might serve and be paid in his brevet rank. This happened frequently before the Civil War but was rare after the war, when more high-ranking officers were available for top commands]
1Although Fort Union was established by Col. E. V. Sumner, he remained department commander while Captain Alexander served as post commander. Alexander received a brevet of brigadier general in 1865 for meritorious service in recruiting Federal armies during the Civil War.
2 Carleton played a conspicuous role in New Mexico history. After the outbreak of the Civil War, he raised and commanded a brigade of California volunteers that helped free New Mexico of Confederate invaders. As commander of the Department of New Mexico from 1862 to 1866, he prosecuted vigorous campaigns against the hostile Apaches and Navajos. At the close of the war he held commissions of major general of volunteers and brevet major general of the Regular Army, but in the post-war reduction of the Army received a regular commission as lieutenant colonel of the 4th Cavalry. He died in 1873.
3 Macrae's career illustrates the slow promotion that was the lot of many frontier officers. Graduating from West Point in 1826, he was posted as 2d lieutenant to the 3d Infantry. Promotion to 1st lieutenant came in 1835, to captain in 1839. After 18 years as a captain he reached the rank of major in 1857 and retired in 1861, having served 35 years in the same regiment. In 1865 the Army recognized his "long and faithful service" by awarding him brevets of lieutenant colonel and colonel. He died in 1878.
4 Cooke's career spanned almost the entire era of the opening of the West, and he himself played a prominent role in the westward movement. He graduated from West Point in 1827, and after 6 years as an infantryman became an officer in the 1st Dragoons. Thereafter he was identified exclusively with the mounted arm, whose organization, equipment, and concept of employment he profoundly influenced through published writings. One of Gen. Stephen W. Kearny's most trusted officers in the conquest of the Southwest during the Mexican War, Cooke led the Mormon Battalion in opening a wagon road from Santa Fe to San Diego, a road used by thousands of immigrants in the California gold rush. He became colonel of the 2d Dragoons in 1859 and brigadier general in 1861. One of the frontier army's outstanding officers, he proved less brilliant in the ""civilized" combat of the Civil War. He retired in 1873 and died in 1895.
5 Fauntleroy is chiefly remembered for his frontier service before the Civil War, especially in the victorious Ute Campaign of 1855. At the outbreak of the Civil War, he resigned from the U.S. Army and accepted a commission in the Confederate Army as brigadier general of Virginia volunteers. He died in 1883.
6 Loring's career was diverse and colorful. He served as an officer in the Florida volunteers during the Seminole war in 1837; and in 1846, with the outbreak of the Mexican War, he received an appointment as captain in the newly formed Regiment of Mounted Riflemen. Brevetted for gallantry at Contreras, Churubusco, and Chapultepec (where he lost an arm), he rose through the ranks to command the Mounted Riflemen. Resigning his commission in 1861, he cast his lot with the Confederacy and served with distinction as a major general. After Appomattox he led a group of ex-Confederates abroad to join the armies of the Khedive of Egypt. For 10 years Loring fought for the Khedive, rising to the rank of general of division before returning to the United States and retirement.
7 One of the prominent Kentucky Crittendens, George B. Crittenden had been with the Regiment of Mounted Riflemen since 1846. Brevetted for gallantry at Contreras and Churubusco in 1847, he had been cashiered from the Army the same year and reinstated the following year. He resigned in 1861 and became a major general in the Confederate Army. He died in 1880.
8 Sibley was promoted to major, 1st Dragoons, on May 13, 1861, and on the same day submitted his resignation from the Army. Five days later, while awaiting action on the resignation, he assumed command of Fort Union. On June 13, acceptance having reached him, he turned over command of Fort Union to Major Chapman and left for the South. The following year, 1862, he was back in New Mexico as a brigadier general in the Confederate Army leading the abortive invasion of New Mexico.
9 Colonel Selden died at Fort Union in 1865, and Fort Selden, established in the spring of that year on the Rio Grande at the southern end of the Jornado del Muerro, was named for him.
10 The legendary Kit Carson, trapper, hunter, explorer, guide, and soldier, led his New Mexico volunteer cavalry in several outstanding campaigns against hostile Indians during the Civil War years. Brevetted brigadier general of volunteers in March 1865 for gallantry in the Battle of Valverde and distinguished service against hostile Indians, Carson was mustered our of the volunteer service on Nov. 22, 1867. He died the following year.
11 Brooke had risen from captain to brigadier general of volunteers during the Civil War and had been brevetted for gallantry at Gettysburg and Spotsylvania Court House. At the close of the war he accepted a Regular Army commission. As brigadier general in 189091, he managed the campaign against the Sioux Ghost Dancers at Pine Ridge Agency, S. Dak., and as a major general fought in Cuba during the Spanish-American War. He retired in 1902.
12 As a captain, Grier had commanded Fort Union in 1856.
13 Major Wade was the son of the powerful Republican senator from Ohio, Benjamin F. Wade. Later, in 1886, as lieutenant colonel of the 9th Cavalry, Wade managed the removal of the Chiricahua Apaches from San Carlos Agency, Ariz., to Florida, a move that proved instrumental in persuading Geronimo to surrender. During the Spanish-American War, Wade served as a major general of volunteers, and in 1903 attained the rank of major general in the Regular Army.
14 The New Mexico historian W. A. Keleher says this about Dudley: ". . . stormy petrel of the military in the Southwest for over a decade. . . . On November 26, 1877, Dudley, then commanding officer at Fort Union, New Mexico, was tried before a court martial on several charges, including alleged disobedience of orders of Brig. Gen. John Pope, commanding the Department of Missouri; villification of and refusal to cooperate with Capt. A. S. Kimball, when ordered to do so by Col. Edward Hatch, commanding the Ninth Cavalry; drunkenness while on duty on April 27, 1877. Dudley was found guilty of some of the charges, not guilty of others, suspended from rank, relieved of command at Fort Union, and deprived of half-pay for three months. On March 8, 1878, Gen. W. T. Sherman ordered the unexecuted portion of the sentence remitted." This was Dudley's second court-martial, the first having occurred at Camp McDowell, Ariz., in 1871. In April 1878 he took command at Fort Stanton, N. Mex., and immediately became involved in the famous Lincoln County war between rival factions of cattlemen. His role in this affair is still controversial. He retired as colonel of the 1st Cavalry in 1889 and spent some years attempting to vindicate his reputation.
15 Whittemore holds the record for number of separate tours as post commander at Fort Union, having served in that capacity eight times between 1876 and 1891.