

The average household size was 2.10 and the average family size was 2.74. Of the 3,272 households, 20.4% had children under the age of 18 living with them, 46.2% were married couples living together, 8.9% had a female householder with no husband present, 42.0% were non-families, and 37.6% of all households were made up of individuals. In terms of ancestry, 39.7% were German, 12.6% were Irish, 11.2% were English, 8.4% were Norwegian, 5.9% were Dutch, and 2.3% were American.

Those of Hispanic or Latino origin made up 2.2% of the population. The racial makeup of the county was 88.6% white, 7.1% American Indian, 0.7% black or African American, 0.4% Asian, 0.3% from other races, and 2.9% from two or more races. There were 4,191 housing units at an average density of 2.4 per square mile (0.93/km 2).

The population density was 4.1 inhabitants per square mile (1.6/km 2). About 7.80% of families and 13.60% of the population were below the poverty line, including 18.90% of those under age 18 and 9.80% of those age 65 or over.Īs of the 2010 census, there were 7,094 people, 3,272 households, and 1,899 families in the county. The per capita income for the county was $17,048. Males had a median income of $30,646 versus $20,017 for females. The median income for a household in the county was $29,631, and the median income for a family was $37,827. For every 100 females age 18 and over, there were 103.80 males. For every 100 females there were 109.80 males. The county population contained 22.80% under the age of 18, 5.80% from 18 to 24, 20.60% from 25 to 44, 28.30% from 45 to 64, and 22.50% who were 65 years of age or older. The average household size was 2.23 and the average family size was 2.82. 32.70% of all households were made up of individuals, and 14.60% had someone living alone who was 65 years of age or older. There were 3,127 households, out of which 23.70% had children under the age of 18 living with them, 50.90% were married couples living together, 8.50% had a female householder with no husband present, and 36.80% were non-families. 33.6% were of German, 12.1% English, 9.5% Norwegian and 7.0% Irish ancestry. 1.74% of the population were Hispanic or Latino of any race. The racial makeup of the county was 90.51% White, 0.32% Black or African American, 6.05% Native American, 0.23% Asian, 0.05% Pacific Islander, 0.30% from other races, and 2.54% from two or more races. There were 3,812 housing units at an average density of 2 per square mile (1/km 2). The population density was 4 people per square mile (2/km 2).

Outside the mountainous area, the county's highest point is its SW corner, at 3,970' (1210m) ASL. The Fall River County terrain contains a mountainous area in the north-central portion, with rolling hills in the rest of the county. Its south borderline abuts the north borderline of the state of Nebraska, and its west borderline abuts the east borderline of the state of Wyoming. Fall River County lies at South Dakota's SW corner.
