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.

Taylor County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 143,208. Its county seat is Abilene. The county was created in 1858 and later organized in 1878. It is named for Edward Taylor, George Taylor, and James Taylor, three brothers who died at the Battle of the Alamo.