2020 census
As of the 2020 census, the county had a population of 10,794. Of the residents, 30.9% were under the age of 18 and 13.8% were 65 years of age or older; the median age was 33.2 years. For every 100 females there were 99.5 males, and for every 100 females age 18 and over there were 96.5 males. 0.0% of residents lived in urban areas and 100.0% lived in rural areas. [12] [13] [14]
The racial makeup of the county was 33.6% White, 0.3% Black or African American, 57.9% American Indian and Alaska Native, 0.4% Asian, 0.6% from some other race, and 7.2% from two or more races. Hispanic or Latino residents of any race comprised 2.2% of the population. [14]
There were 3,610 households in the county, of which 40.2% had children under the age of 18 living with them and 30.4% had a female householder with no spouse or partner present. About 26.4% of all households were made up of individuals and 9.7% had someone living alone who was 65 years of age or older. [13]
There were 4,065 housing units, of which 11.2% were vacant. Among occupied housing units, 59.9% were owner-occupied and 40.1% were renter-occupied. The homeowner vacancy rate was 2.0% and the rental vacancy rate was 7.4%. [13]
2010 census
As of the 2010 census, there were 10,425 people, 3,553 households, and 2,548 families residing in the county. The population density was 4.4 inhabitants per square mile (1.7/km2). There were 4,063 housing units at an average density of 1.7 per square mile (0.66/km2). The racial makeup of the county was 60.4% American Indian, 35.8% white, 0.4% Asian, 0.1% black or African American, 0.2% from other races, and 3.0% from two or more races. Those of Hispanic or Latino origin made up 1.3% of the population. In terms of ancestry, 20.0% were Norwegian, 16.3% were German, 6.1% were Irish, and 1.3% were American.
Of the 3,553 households, 42.4% had children under the age of 18 living with them, 42.9% were married couples living together, 20.5% had a female householder with no husband present, 28.3% were non-families, and 24.2% of all households were made up of individuals. The average household size was 2.88 and the average family size was 3.41. The median age was 31.6 years.
The median income for a household in the county was $37,451 and the median income for a family was $50,146. Males had a median income of $39,008 versus $34,725 for females. The per capita income for the county was $17,821. About 15.8% of families and 21.5% of the population were below the poverty line, including 28.6% of those under age 18 and 10.9% of those age 65 or over.
United States
Montana 
