Major highways

• U.S. Highway 12
• Montana Highway 3

Adjacent counties

National protected area

• Lewis and Clark National Forest (part)

2020 census

As of the 2020 census, there were 823 people living in the county.^{[citation needed]}

2010 census

As of the 2010 census, there were 884 people, 363 households, and 239 families residing in the county. The population density was 0.8 inhabitants per square mile (0.31/km²). There were 476 housing units at an average density of 0.4 per square mile (0.15/km²). The racial makeup of the county was 94.0% white, 1.0% American Indian, 0.7% Asian, 2.1% from other races, and 2.1% from two or more races. Those of Hispanic or Latino origin made up 3.5% of the population. In terms of ancestry, 38.9% were German, 19.5% were English, 18.4% were Irish, 10.1% were Polish, 9.0% were American, 7.3% were Danish, 6.4% were Dutch, and 6.2% were Norwegian.

Of the 363 households, 20.7% had children under the age of 18 living with them, 55.4% were married couples living together, 5.2% had a female householder with no husband present, 34.2% were non-families, and 29.5% of all households were made up of individuals. The average household size was 2.19 and the average family size was 2.68. The median age was 48.8 years.

The median income for a household in the county was $35,726 and the median income for a family was $48,750. Males had a median income of $33,750 versus $27,938 for females. The per capita income for the county was $19,319. About 3.4% of families and 10.9% of the population were below the poverty line, including 21.7% of those under age 18 and 5.8% of those age 65 or over.

Towns

• Lavina
• Ryegate (county seat)

Census-designated place

• Golden Valley Colony

Unincorporated communities