Adjacent counties and rural municipalities

Major highways

• U.S. Route 2
• U.S. Route 87

National protected areas

• Creedman Coulee National Wildlife Refuge
• Lake Thibadeau National Wildlife Refuge

2020 census

As of the 2020 census, there were 16,309 people living in the county.^{[citation needed]}

2010 census

As of the 2010 census, there were 16,096 people, 6,275 households, and 4,020 families living in the county. The population density was 5.6 inhabitants per square mile (2.2/km²). There were 7,250 housing units at an average density of 2.5 per square mile (0.97/km²). The racial makeup of the county was 73.9% white, 21.7% American Indian, 0.4% Asian, 0.3% black or African American, 0.3% from other races, and 3.3% from two or more races. Those of Hispanic or Latino origin made up 2.3% of the population. In terms of ancestry, 28.9% were German, 18.5% were Norwegian, 12.7% were Irish, 9.2% were English, and 3.0% were American.

Of the 6,275 households, 32.5% had children under the age of 18 living with them, 46.3% were married couples living together, 11.9% had a female householder with no husband present, 35.9% were non-families, and 29.8% of all households were made up of individuals. The average household size was 2.47 and the average family size was 3.10. The median age was 35.1 years.

The median income for a household in the county was $43,606 and the median income for a family was $55,963. Males had a median income of $44,286 versus $28,908 for females. The per capita income for the county was $21,420. About 12.4% of families and 17.9% of the population were below the poverty line, including 24.0% of those under age 18 and 9.6% of those age 65 or over.

City

• Havre (county seat)

Town

• Hingham

Census-designated places

Unincorporated communities