page_title: Jefferson County, Kansas
section_title: Demographics
hierarchical_section_title: Jefferson County, Kansas / Demographics
context_page_description: Jefferson County is a county located in the U.S. state of Kansas. At the 2010 census, the county population was 19,126. Its county seat is Oskaloosa, and its most populous city is Valley Falls.
context_section_description: Jefferson County is included in the Topeka, KS Metropolitan Statistical Area.
  At the 2000 Census, there were 18,426 people, 6,830 households and 5,190 families residing in the county. The population density was 34 per square mile (13/km²). There were 7,491 housing units at an average density of 14 per square mile (5/km²). The racial makeup of the county was 96.70% White, 0.92% Native American, 0.37% Black or African American, 0.17% Asian, 0.01% Pacific Islander, 0.42% from other races, and 1.41% from two or more races. Hispanic or Latino of any race were 1.28% of the population.
  There were 6,830 households, of which 35.70% had children under the age of 18 living with them, 65.20% were married couples living together, 7.00% had a female householder with no husband present, and 24.00% were non-families. 20.10% of all households were made up of individuals, and 9.30% had someone living alone who was 65 years of age or older. The average household size was 2.66 and the average family size was 3.07.
  27.40% of the population were under the age of 18, 7.00% from 18 to 24, 28.00% from 25 to 44, 24.90% from 45 to 64, and 12.80% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 102.60 males. For every 100 females age 18 and over, there were 98.90 males.
  The median household income was $45,535 and the median family income was $50,557. Males had a median income of $36,174 compared with $25,468 for females. The per capita income for the county was $19,373. About 5.30% of families and 6.70% of the population were below the poverty line, including 6.90% of those under age 18 and 7.70% of those age 65 or over.
caption: Population pyramid