Officially created: February 16, 1877
The following counties removed from Custer County territory:
Yellowstone – February 26, 1883
Rosebud – February 11, 1901
Fallon – December 9, 1913
Wibaux – August 17, 1914
Prairie – February 5, 1915
Carter – February 22, 1917
Powder River – April 1, 1919
First District Court Judge ………… .. George R. Milburn – 1889
First Marriage License issued ….. .. October 1877
When Custer County was formed, it was larger than the present state of Pensylvania. It began shrinking in 1883 when Yellowstone County was taken out, and afterward lost pieces to Park, SweetGrass, Carbon, Rosebud, Fallon Wibaux, Prairie, Carter and Powder River. It is now the 10th in size in Montana counties.
Miles City, county seat of Custer County is in the center of the great Yellowstone Valley of eastern Montana. Historically speaking, Miles”City came into existence on the heels of the military expedition sent into the valley of the Yellowstone from Fort Leavenworth, Kansas, following the Battle of the Little Big Horn on June 25, 1876, when General George A. Custer and his immediate command of five troops of the 7th Calvary were annihilated by the Sioux Indians under Sitting Bull.
It is interesting to know the origin of the community. Colonel (later General) Nelson A. Miles, in command of six companies of the 5th Infantry, stationed in the summer of 1876 at Fort Leavenworth, received orders to proceed to the valley of the Yellowstone in Montana and there to establish a cantonment from which he was to conduct a campaign designed to compel the wandering bands of Indians to return to their respective reservations.
Arriving in the early fall, Miles conferred with General Alfred H. Terry, in command of the Department of the Dakotas, who was still in the field following the Custer battle. Subsequently he selected a site at the mouth of Tongue River on which to build the cantonment. The Army Engineers surveyed a tract of land ten miles square and established a reservation. It was just across this reservation on the east and on the south bank of the Yellowstone River that the first village was set up. A year later when the War Department abandoned that portion of the military reservation lying east of the Tongue River, the village, figuratively speaking, moved itself, cabins and appurtenances to the present site. The new community was named Miles City in honor of the commanding officer at the cantonment.