The Katy Trail State Park is a state park in the U.S. state of Missouri that contains the Katy Trail, a recreational rail trail that runs 240mi in the right-of-way of the former Missouri–Kansas–Texas Railroad. Running largely along the northern bank of the Missouri River, it is the country's longest Rails-to-Trails trail. The trail is open for use by hikers, joggers, and cyclists year-round, from sunrise to sunset. Its hard, flat surface is of "limestone pug" (crushed limestone).The nickname "Katy" comes from the phonetic pronunciation of 'KT' in the railroad's abbreviated name, MKT. Sections of the Katy are also part of the Lewis and Clark National Historic Trail and the American Discovery Trail.HistoryConversion of right-of-way to a trail was made possible by the National Trails System Act of 1968. In 1982, the city of Columbia opened the MKT Trail on an abandoned spur of the Katy as one of the first rails-to-trails pilot projects in the United States.