Founded in February 2, 1865, Custer County is one of 56 counties in the state of Montana. Historically, Custer County was one of the 9 original counties. The city of Miles City is the county seat. With FIPS code of 17, Custer County has a population of 11,916 and area of 3,783 square miles (9,798 km2).
List of all cities in Custer County, MT alphabetically
| City/Town | Postal Code | Area Code |
| Ismay, MT | 59336 | 406 |
| Kinsey, MT | 59338 | 406 |
| Miles City, MT | 59301 | 406 |
| Volborg, MT | 59351 | 406 |