Clay County was formed from Cooke County, created December 24, 1857, and organized August 6, 1860. It was disorganized in 1862 because of Indian raids and reorganized August 4, 1873. Henrietta served as headquarters for buffalo hunters until 1878. The first Hereford cattle in Texas were brought to Clay County in 1875 from Beecher, Illinois, by William S. Ikard. The original county seat was Cambridge, which was moved to Henrietta in 1874.