In the 1890s, Edward T. "E.T." Guymon, president of the Inter-State Land and Town Company, purchased a section of land west of the Beaver River, also known as the North Canadian River. The site grew very rapidly after the Chicago, Rock Island and Pacific Railway (Rock Island) built a line from Liberal, Kansas, to Texhoma, Texas, in 1901. A community, first named Sanford by the U.S. Post Office Department, was situated along the line. It was renamed Guymon a month later by postal officials to avoid confusion with the town of Stratford, Texas, which was further down the line. Guymon incorporated in 1901. The town plat was filed in Beaver County, Oklahoma Territory, in 1904.