MASON, TEXAS. Mason, the county seat of Mason County, is on Comanche Creek at the junction of Interstate Highway 87/State Highway 29 and Ranch roads 1871 and 386, in the central part of the county. It grew up around Fort Mason, established in 1851, although some settlers were already in the area before that date. One of the first, William S. Gamel, is thought to have arrived around 1846. Peter Birk and Henry Hick were among the first German settlers who moved west from Fredericksburg. Near the site of present Mason is Gamel Spring, where John O. Meusebach is thought to have signed a treaty with Comanche Chief Ketemoczy in 1847.