Ellis County is a county located in the U.S. state of Kansas. Its county seat and most populous city is Hays. As of the 2020 census, the county population was 28,934. The county was named for George Ellis, a first lieutenant of the Twelfth Kansas Infantry. Ellis County is the official German Capital of Kansas. German immigrants settled in Hays, Ellis, Victoria, and nearby villages in the 1870s and 1880s.

Hays is a city in and the county seat of Ellis County, Kansas, United States. The largest city in northwestern Kansas, it is the economic and cultural center of the region. As of the 2020 census, the population of the city was 21,116. It is also a college town, home to Fort Hays State University.