McCurtain County is a county in the southeastern corner of the U.S. state of Oklahoma. As of the 2020 census, its population was 30,814. Its county seat is Idabel. It was formed at statehood from part of the earlier Choctaw Nation in Indian Territory. The name honors an influential Choctaw family who lived in the area. Green McCurtain was the last chief when Okla…McCurtain County is a county in the southeastern corner of the U.S. state of Oklahoma. As of the 2020 census, its population was 30,814. Its county seat is Idabel. It was formed at statehood from part of the earlier Choctaw Nation in Indian Territory. The name honors an influential Choctaw family who lived in the area. Green McCurtain was the last chief when Oklahoma became a state in 1907.