Fort Ellsworth was the first frontier fort established in the Kanopolis area. It was built by the United States Army in August 1864 at the junction of the Fort Riley-Fort Larned Road and the Smoky Hill Trail, near the Smoky Hill River. Its purpose was to protect construction of the Union Pacific railroad from Native American raids. In November, 1866 Fort Ellsworth changed its name to Fort Harker after the death of General G.H. Charles Harker, who was killed in battle in 1864.