Cooke County is a county in the U.S. state of Texas. At the 2020 census, its population was 41,668. The county seat is Gainesville. The county was founded in 1848 and organized the next year. It is named for William Gordon Cooke, a soldier during the Texas Revolution. It is a part of the Texoma region.

Gainesville is a city in and the county seat of Cooke County, Texas, United States. Its population was 17,394 at the 2020 census. It is part of the Texoma region and is an important Agri-business center.