Wilson County is a county located in Southeast Kansas. Its county seat is Fredonia. As of the 2020 census, the county population was 8,624. The county was named after Hiero Wilson, a colonel in the American Civil War.

Fredonia is a city in and the county seat of Wilson County, Kansas, United States. As of the 2020 census, the population of the city was 2,151. The city was founded in 1868, and saw considerable expansion in the early 20th century, with a fossil fuel boom.