In 1820, the U.S. government granted the land now known as Johnston County to the Choctaw tribe. Many of the Choctaws began moving to the new land in Indian Territory in 1830. The rest followed Chickasaw tribe, who were closely related to the Choctaw, formally separated from the Choctaw Nation in the late 1830s, relocating to the western part of the Choctaw Nation. The Chickasaw Nation named the town of Tishomingo as its capital and built a brick capitol building there in 1856.