2020 census
As of the 2020 census, the county had a population of 6,226. [10]
Of the residents, 23.4% were under the age of 18 and 23.8% were 65 years of age or older; the median age was 45.1 years. For every 100 females there were 99.4 males, and for every 100 females age 18 and over there were 99.6 males. [11]
0.0% of residents lived in urban areas and 100.0% lived in rural areas. [12]
The racial makeup of the county was 91.3% White, 0.3% Black or African American, 1.6% American Indian and Alaska Native, 0.3% Asian, 0.7% from some other race, and 5.6% from two or more races. Hispanic or Latino residents of any race comprised 1.4% of the population. [10]
There were 2,490 households in the county, of which 26.6% had children under the age of 18 living with them and 21.5% had a female householder with no spouse or partner present. About 30.3% of all households were made up of individuals and 16.3% had someone living alone who was 65 years of age or older. [11]
There were 2,935 housing units, of which 15.2% were vacant. Among occupied housing units, 74.1% were owner-occupied and 25.9% were renter-occupied. The homeowner vacancy rate was 1.3% and the rental vacancy rate was 8.3%. [11]
2010 census
As of the 2010 census, there were 6,073 people, 2,450 households, and 1,643 families residing in the county. The population density was 2.7 inhabitants per square mile (1.0/km2). There were 2,892 housing units at an average density of 1.3 units per square mile (0.50 units/km2). The racial makeup of the county was 96.3% white, 1.4% American Indian, 0.1% Asian, 0.2% from other races, and 1.9% from two or more races. Those of Hispanic or Latino origin made up 1.3% of the population. In terms of ancestry, 40.2% were German, 14.7% were Norwegian, 14.5% were Irish, 11.9% were English, 6.4% were Swedish, 6.0% were Dutch, and 4.3% were American.
Of the 2,450 households, 25.7% had children under the age of 18 living with them, 58.2% were married couples living together, 6.0% had a female householder with no husband present, 32.9% were non-families, and 29.3% of all households were made up of individuals. The average household size was 2.29 and the average family size was 2.83. The median age was 45.8 years.
The median income for a household in the county was $39,516 and the median income for a family was $49,102. Males had a median income of $34,824 versus $24,419 for females. The per capita income for the county was $20,509. About 11.0% of families and 12.8% of the population were below the poverty line, including 13.3% of those under age 18 and 13.5% of those age 65 or over.
United States
Montana 
