The county was created in 1914 and organized in 1915, and was formed from the original counties of Nowlin and most of Sterling, which had previously been absorbed by Stanley County. It is named for Haakon VII, who became king of Norway in 1905. It is the only county in South Dakota named for a non-American person and is one of only nine counties in South Dakota named for persons who did not live in South Dakota (Clay, Custer, Douglas, Grant, Hamlin, Lincoln, McPherson, and Meade are the other eight). Most of the 66 South Dakota counties are named for early South Dakota officials or legislators, or for physical features (Fall River and Lake), or are derived from Indian words (Minnehaha and Yankton), or from counties in other states (Jones and Walworth), with one (Aurora) named for a Roman goddess, one for an animal (Buffalo), and one (Union) for a concept.
As of the census of 2000, there were 2,196 people, 870 households, and 620 families residing in the county. The population density was 1 person per square mile (0,5/km²). There were 1,002 housing units at an average density of 1 per square mile (0/km²). The racial makeup of the county was 96.40% White, 2.50% Native American, 0.09% Asian, and 1.00% from two or more races. 0.59% of the population were Hispanic or Latino of any race.
There were 870 households out of which 32.60% had children under the age of 18 living with them, 63.60% were married couples living together, 4.80% had a female householder with no husband present, and 28.70% were non-families. 26.00% of all households were made up of individuals and 13.10% had someone living alone who was 65 years of age or older. The average household size was 2.47 and the average family size was 3.00.
In the county, the population was spread out with 25.70% under the age of 18, 7.00% from 18 to 24, 25.20% from 25 to 44, 24.10% from 45 to 64, and 18.00% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 96.60 males. For every 100 females age 18 and over, there were 97.30 males.
The median income for a household in the county was $29,894, and the median income for a family was $35,958. Males had a median income of $25,098 versus $18,913 for females. The per capita income for the county was $16,780. About 12.00% of families and 13.90% of the population were below the poverty line, including 18.70% of those under age 18 and 16.00% of those age 65 or over.