The terrain of McCook County consists of rolling hills, mostly devoted to agriculture.[6] The terrain slopes to the south and southwest; its highest point is near its northeast corner, at 1,798 ft (548 m) ASL.[7] The county has a total area of 577 square miles (1,490 km2), of which 574 square miles (1,490 km2) is land and 2.7 square miles (7.0 km2) (0.5%) is water.[8]
U.S. Decennial Census[10] 1790-1960[11] 1900-1990[12] 1990-2000[13] 2010-2020[1]
2020 census
As of the 2020 census, there were 5,682 people, 2,159 households, and 1,505 families residing in the county.[14] The population density was 9.9 inhabitants per square mile (3.8/km2). There were 2,448 housing units.
2010 census
As of the 2010 census, there were 5,618 people, 2,168 households, and 1,535 families in the county. The population density was 9.8 inhabitants per square mile (3.8/km2). There were 2,491 housing units at an average density of 4.3 units per square mile (1.7 units/km2). The racial makeup of the county was 98.0% white, 0.4% American Indian, 0.1% Pacific islander, 0.1% Asian, 0.1% black or African American, 0.6% from other races, and 0.7% from two or more races. Those of Hispanic or Latino origin made up 1.8% of the population. In terms of ancestry, 61.5% were German, 12.8% were Irish, 11.1% were Norwegian, 7.4% were Swedish, 6.2% were Dutch, 5.2% were English, and 3.5% were American.
Of the 2,168 households, 30.4% had children under the age of 18 living with them, 61.0% were married couples living together, 6.0% had a female householder with no husband present, 29.2% were non-families, and 26.2% of all households were made up of individuals. The average household size was 2.45 and the average family size was 2.94. The median age was 42.7 years.
The median income for a household in the county was $42,022 and the median income for a family was $57,287. Males had a median income of $35,951 versus $29,750 for females. The per capita income for the county was $25,502. About 5.2% of families and 7.9% of the population were below the poverty line, including 6.7% of those under age 18 and 14.4% of those age 65 or over.
Politics
McCook County voters usually vote Republican. Although the county was one only 130 nationwide to support favorite sonGeorge McGovern in 1972, it has selected the Democratic nominee in only six other elections since South Dakota's statehood, and none since 1980.
United States presidential election results for McCook County, South Dakota[15]