Jack County is a county located in the north central part of the U.S. state of Texas. As of the 2020 census, its population was 8,472. Its county seat is Jacksboro. The county was created in 1856 and organized the next year. It is named for Patrick Churchill Jack and his brother William Houston Jack, both soldiers of the Texas Revolution.

Young County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 17,867. Its county seat is Graham. The county was created in 1856 and organized in 1874. It is named for William Cocke Young, an early Texas settler and soldier.