Marion County is a county located in the U.S. state of Kansas. Its county seat is Marion and its most populous city is Hillsboro. As of the 2020 census, the county population was 11,823. The county was named in honor of Francis Marion, a brigadier general of the American Revolutionary War, known as the "Swamp Fox".

Marion is a city in, and the county seat of, Marion County, Kansas, United States. As of the 2020 census, the population of the city was 1,922. The city was named in honor of Francis Marion, a brigadier general of the American Revolutionary War, known as the "Swamp Fox".