| County: | Custer County |
| State: | Montana |
| Founded Date: | June 2 |
| Founded Year: | 1865 |
| Seat Wl: | Miles City |
| Largest City Wl: | Miles City |
| Area Total Sq Mi: | 3793 |
| Area Land Sq Mi: | 3783 |
| Area Water Sq Mi: | 9.9 |
| Area Percentage: | 0.3 |
| Population As Of: | 2020 |
| Population Total: | 11867 |
| Pop Est As Of: | 2022 |
| Population Est: | 12032 |
| Population Density Sq Mi: | auto |
| Time Zone: | Mountain |
| Ex Image: | Miles City MT Custer County Courthouse.jpg |
| Ex Image Cap: | Custer County Courthouse in Miles City |
| Website: | https://custercountymt.com/ |
| District: | 2nd |
| Footnotes: |
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Custer County is a county located in the U.S. state of Montana. As of the 2020 census, the population was 11,867.[1] Its county seat is Miles City.[2] The county was established on June 2, 1865, as one of the nine original counties of the Territory of Montana named Big Horn County,[3] and was renamed on February 16, 1877, in honor of Lieutenant Colonel George Armstrong Custer.[4]
According to the United States Census Bureau, the county has a total area of, of which is land and (0.3%) is water.[5]
According to the Köppen Climate Classification system, Custer County has a mostly cold semi-arid climate, abbreviated "BSk" on climate maps.
As of the 2020 census, there were 11,867 people living in the county.
As of the 2010 census, there were 11,699 people, 5,031 households, and 3,014 families living in the county. The population density was . There were 5,560 housing units at an average density of . The racial makeup of the county was 95.5% white, 1.7% American Indian, 0.3% black or African American, 0.3% Asian, 0.1% Pacific islander, 0.5% from other races, and 1.6% from two or more races. Those of Hispanic or Latino origin made up 2.2% of the population. In terms of ancestry, 33.6% were German, 18.3% were Irish, 14.3% were American, 14.1% were Norwegian, and 10.6% were English.
Of the 5,031 households, 27.3% had children under the age of 18 living with them, 46.6% were married couples living together, 9.0% had a female householder with no husband present, 40.1% were non-families, and 34.3% of all households were made up of individuals. The average household size was 2.24 and the average family size was 2.88. The median age was 42.1 years.
The median income for a household in the county was $38,913 and the median income for a family was $49,011. Males had a median income of $37,535 versus $26,576 for females. The per capita income for the county was $21,676. About 12.4% of families and 15.7% of the population were below the poverty line, including 19.8% of those under age 18 and 14.6% of those age 65 or over.
Agriculture (dryland farming) and cattle raising provide the bulk of Custer County economy.[6] Miles City serves as the center of commerce in an area extending for 100 miles in every direction.[7] As of 2009 the county's largest employers were Holy Rosary Healthcare, Sanjel USA, Stockman Bank, and Walmart.[7]