The Great Western Trail is a rail trail in Iowa's Des Moines metropolitan area. It is 16.5 miles (26.6 km) long and paved with asphalt. The trail follows the route of an abandoned line of the Chicago, St. Paul and Kansas City Railroad, constructed in 1899 and last operated by the Chicago and North Western Railway. It runs between southwestern Des Moines at its north end and Martensdale at the south, passing through suburban areas, fields and farmland, and the wooded valley of the North River. The trail is maintained by the Conservation Boards of Polk and Warren Counties.