Cheyenne County is a county located in the northwest corner of the U.S. state of Kansas. Its county seat and most populous city is St. Francis. As of the 2020 census, the county population was 2,616. The county was named after the Cheyenne tribe.

St. Francis is a city in and the county seat of Cheyenne County, Kansas, United States. As of the 2020 census, the population of the city was 1,263.