County History
How Jack County Got Its Name and Grew
Jack County was created in 1856 and named for two brothers who fought in the Texas Revolution, with Jacksboro growing from a frontier settlement into the county seat.
The Texas Legislature created Jack County on August 27, 1856. It was named after William H. and Patrick C. Jack, who were Texas Revolution participants. The original county seat was called Mesquiteville, after the mesquite trees there. It was later renamed Jacksboro.
The county grew slowly at first due to raids on settlers. After Fort Richardson was established in 1867, settlement increased rapidly. By 1880 the population was over 6,000. Cattle ranching came first, then farming. Agriculture, oil and gas, and oilfield services have all shaped the local economy since then. The Handbook of Texas at tshaonline.org has a detailed county history.
Source to confirm: Handbook of Texas — Jack County