The terrain of Turner County consists of rolling hills, carved by gullies and drainages. The area is largely devoted to agriculture. The terrain slopes to the south and east; its highest point is along its west boundary line, at 1,578' ASL. The county has a total area of, of which is land and is water.
As of the 2000 United States Census, there were 8,849 people, 3,510 households, and 2,478 families in the county. The population density was 14 people per square mile. There were 3,852 housing units at an average density of 6 per square mile. The racial makeup of the county was 98.86% White, 0.15% Black or African American, 0.27% Native American, 0.17% Asian, 0.12% from other races, and 0.43% from two or more races. 0.41% of the population were Hispanic or Latino of any race. There were 3,510 households out of which 31.60% had children under the age of 18 living with them, 61.90% were married couplesliving together, 5.60% had a female householder with no husband present, and 29.40% were non-families. 26.50% of all households were made up of individuals and 14.80% had someone living alone who was 65 years of age or older. The average household size was 2.46 and the average family size was 2.99. The county population contained 25.80% under the age of 18, 6.20% from 18 to 24, 24.80% from 25 to 44, 22.80% from 45 to 64, and 20.40% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 97.20 males. For every 100 females age 18 and over, there were 93.90 males. The median income for a household in the county was $36,059, and the median income for a family was $42,704. Males had a median income of $28,833 versus $20,075 for females. The per capita income for the county was $17,343. About 5.70% of families and 7.20% of the population were below the poverty line, including 6.30% of those under age 18 and 11.30% of those age 65 or over.
2010 census
As of the 2010 United States Census, there were 8,347 people, 3,452 households, and 2,363 families in the county. The population density was. There were 3,939 housing units at an average density of. The racial makeup of the county was 97.5% white, 0.8% American Indian, 0.2% black or African American, 0.2% Asian, 0.3% from other races, and 0.9% from two or more races. Those of Hispanic or Latino origin made up 1.3% of the population. In terms of ancestry, 47.7% were German, 18.4% were Norwegian, 11.3% were Danish, 9.4% were Irish, 8.5% were Dutch, and 2.7% were American. Of the 3,452 households, 29.0% had children under the age of 18 living with them, 58.7% were married couples living together, 5.9% had a female householder with no husband present, 31.5% were non-families, and 27.4% of all households were made up of individuals. The average household size was 2.37 and the average family size was 2.87. The median age was 43.7 years. The median income for a household in the county was $48,068 and the median income for a family was $57,881. Males had a median income of $37,622 versus $27,459 for females. The per capita income for the county was $22,871. About 4.7% of families and 7.7% of the population were below the poverty line, including 8.9% of those under age 18 and 9.1% of those age 65 or over.
Culture
Turner County hosts the oldest county fair in the Dakotas. It held its first fair on October 13–16, 1880. The Turner County Agriculture Society was organized in March 1880. Its stated purpose was to showcase the agricultural successes of the new county. The fair was held at various locations over the years, but has been at its current location east of Parker for well over half a century.
