Fort Mason was established July 6, 1851 in what later became Mason County. It was named in honor of Lieut. George Thomson Mason, United States Army Second Lieutenant killed in the Thornton Affair during the Mexican–American War near Brownsville, April 25, 1846. At various times from 1856 to 1861 this was the home fort for Albert Sidney Johnston, George H. Thomas, Earl Van Dorn and Robert E. Lee. The fort was abandoned by the military in the 1870s, and restored by a group of local citizens in 1975. Designated a Recorded Texas Historic Landmark in 1936 Marker number 11275 .