[4] The county is named for James Coryell, a frontiersman and Texas Ranger who was killed by Caddo Indians.

The Tonkawa, Lipan Apache, Kiowa, and Comanche were among the tribes who migrated through the area at various periods.

[8] Settlers began moving into the area after Fort Gates was established at Gatesville.

[9] According to the U.S. Census Bureau, the county has a total area of 1,057 square miles (2,740 km2), of which 4.7 sq mi (12 km2) (0.4%) are covered by water.

Of the eight Texas Department of Criminal Justice general correctional facilities for women, which include five prisons and three state jails,[17] five of the units,[18] including four prisons and one state jail,[17] are in the City of Gatesville.

[23] In addition the Mountain View Unit, a prison with the State of Texas female death row, is in Gatesville.

[23] In 1995, of the counties in Texas, Coryell had the third-highest number of state prisons and jails, after Walker and Brazoria.

[26] School districts include:[29] All of the county is in the service area of Central Texas College.