The terrain of McCook County consists of rolling hills, mostly devoted to agriculture. The terrain slopes to the south and southwest; its highest point is near its NE corner, at 1,798' ASL. The county has a total area of, of which is land and is water.
As of the 2000 United States Census, there were 5,832 people, 2,204 households, and 1,558 families in the county. The population density was 10 people per square mile. There were 2,383 housing units at an average density of 4 per square mile. The racial makeup of the county was 98.87% White, 0.05% Black or African American, 0.36% Native American, 0.21% Asian, 0.15% from other races, and 0.36% from two or more races. 0.77% of the population were Hispanic or Latino of any race. There were 2,204 households out of which 34.10% had children under the age of 18 living with them, 62.10% were married couplesliving together, 5.10% had a female householder with no husband present, and 29.30% were non-families. 26.80% of all households were made up of individuals and 15.60% had someone living alone who was 65 years of age or older. The average household size was 2.58 and the average family size was 3.15. The county population Contained 28.40% under the age of 18, 6.20% from 18 to 24, 25.50% from 25 to 44, 20.40% from 45 to 64, and 19.50% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 99.50 males. For every 100 females age 18 and over, there were 97.20 males. The median income for a household in the county was $35,396, and the median income for a family was $42,609. Males had a median income of $28,390 versus $21,073 for females. The per capita income for the county was $16,374. About 5.50% of families and 8.10% of the population were below the poverty line, including 8.90% of those under age 18 and 8.80% of those age 65 or over.
2010 census
As of the 2010 United States Census, there were 5,618 people, 2,168 households, and 1,535 families in the county. The population density was. There were 2,491 housing units at an average density of. 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. In no national election since 1976 has the county selected a Democratic Party candidate.
