Callahan County is a county located in the U.S. state of Texas. As of the 2020 census, the population was 13,708. Its county seat is Baird. The county was founded in 1858 and later organized in 1877. It is named for James Hughes Callahan, an American soldier in the Texas Revolution. Callahan County is included in the Abilene, Texas metropolitan statistical area.

Baird is a city and the county seat of Callahan County, Texas, United States. Its population was 1,479 at the 2020 census. The city is named after Matthew Baird, the owner and director of the Texas and Pacific Railway. The railway depot is now operated as the visitor center and a transportation museum.