Graham County is a county located in the U.S. state of Kansas. Its county seat and most populous city is Hill City. As of the 2020 census, the county population was 2,415. The county was named for John Graham, a captain in the American Civil War that died during the Battle of Chickamauga. The county is home to Nicodemus, founded 1877, which is the only remaining western town established by African Americans during the Reconstruction Period following the American Civil War.