Ellsworth County is a county located in the U.S. state of Kansas. Its county seat and most populous city is Ellsworth. As of the 2020 census, the county population was 6,376. The county was named after Fort Ellsworth.

Ellsworth is a city in and the county seat of Ellsworth County, Kansas, United States. As of the 2020 census, the population of the city was 3,066. Known as a cow town in the 1870s, when the Kansas Pacific Railroad operated a stockyard here for shipping cattle to eastern markets, in the 21st century, it serves as the trading center of the rural county.