William G. Cooke established Fort Johnson in 1840 as part of the defense of the Military Road from Red River to Austin. It was named in honor of Colonel Francis W. Johnson (1799-1888), commander of the Texas Army at the capture of San Antonio on December 10, 1835. It was also the rendezvous point for the Snively Expedition, which set out on April 25, 1843. The settlement in the vicinity was known as Georgetown.