Altus is a city in and the county seat of Jackson County, Oklahoma, United States. The population was 18,729 at the 2020 census.

Jackson County is a county located in the southwestern corner of the U.S. state of Oklahoma. As of the 2020 census, the population was 24,785. Its county seat is Altus. According to the Encyclopedia of Oklahoma History and Culture, the county was named for two historical figures: President Andrew Jackson and Confederate General Stonewall Jackson. One source states that the county was named only for the former president, while an earlier source states it was named only for General Stonewall Jackson.