The Miles City Court complex has within it the Custer County Court, more formally called the Custer County District Court (Phone No. 406-874-3326, Fax 874-3451) and the Miles City Justice Court (Phone No. 406-874-3408, Fax 874-3452). Both of these courts are in the Sixteenth judicial circuit of Montana. The justice court has the responsibility of handling civic and traffic infraction from throughout the county except those occurring within the city limits of Miles city. You will find IS 94 running through Custer county and it meets US 12 and SR 59.

It is sometimes believed that wild West history began around 1876 in this county. Custer county at one time covered a much larger area than it does today. Starting about 1883, Yellowstone Park, SweetGrass, Carbon, Rosebud, Fallon Wibaux, Prairie, Carter and Powder River county grabbed pieces of Custer county for their creation. Miles City owes its formation to the establishment of a military reservation at the mouth of the Tongue River. The village established as a part of the reservation was located on the East and South banks of the Yellowstone river. When the War department abandoned the portion of the river on the East bank, all was moved to the present site of Miles City.