Ellis County (county code EL) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 28,452. Its county seat and most populous city is Hays.The Hays, KS Micropolitan Statistical Area includes all of Ellis County.Ellis County is the official German Capital of Kansas. German immigrants settled in Hays, Ellis, Victoria, and nearby villages in the 1870s and 1880s.