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.

Jacksboro is a city in Jack County, Texas, in the United States. Its population was 4,184 at the 2020 census. U.S. Highways 281 and 380, and Texas State Highways 114 and 199 intersect at Jacksboro, which is the county seat of Jack County.