Kanopolis is a city in Ellsworth County, Kansas, United States. The town is built on the site of Fort Harker, a United States Army post that housed infantry and cavalry troops involved in the Indian Wars from 1867 to 1872. As of the 2010 census, the city population was 492.
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. Within two years of its creation, the fort had grown in importance as a military staging post and supply depot for forts further west, and needed to expand to continue meeting its mission. On November 17, 1866, the Army ordered the construction of Fort Harker about 1.6 km (1 mile) northeast of Fort Ellsworth. Fort Ellsworth was closed in early 1867, and the town of Ellsworth was founded in its place. For the next five years, Fort Harker became one of the most important military stations west of the Missouri River.
With the Indian Wars and the railroads both moving further west, Fort Harker was no longer needed as a military installation. It was officially ordered closed on April 8, 1872 and over the next several months was sold to developers. The new town was given the name of Kanopolis because it was envisioned as the "Central Metropolis" of the state and in due time was to be its capitol. It was laid out to provide for a city of 150,000 people by the Kanopolis Land Company.