Chase County is a county located in the U.S. state of Kansas. Its county seat and most populous city is Cottonwood Falls. As of the 2020 census, the county population was 2,572. The county was named for Salmon Chase, a U.S. Senator from Ohio that was a Kansas statehood advocate.

Cottonwood Falls is the largest city and county seat of Chase County, Kansas, United States. As of the 2020 census, the population of the city was 851. It is located south of Strong City along the south side of the Cottonwood River.