Custer County is a county located in the U.S. state of Oklahoma. As of the 2020 census, the population was 28,513. Its county seat is Arapaho. The county was named in honor of General George Armstrong Custer.

Roger Mills County is a county located in the western part of the U.S. state of Oklahoma. As of the 2020 census, the population was 3,442, making it the fourth-least populous county in Oklahoma. Its county seat is Cheyenne. The county was created in 1891.