[1] It runs 240 miles (390 km), largely along the northern bank of the Missouri River, in the right-of-way of the former Missouri–Kansas–Texas Railroad.

The nickname "Katy" comes from the phonetic pronunciation of "KT", a short form of the railroad's abbreviated name, MKT.

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.

The Rock Island Spur starts at Windsor, on the Katy Trail, and runs 47 miles northwest towards Kansas City.

[7][8] A settlement to allow the use of this portion of the Rock Island corridor was reached between Missouri Governor Matt Blunt and Ameren as partial compensation for a flood which devastated Johnson's Shut-ins State Park after the failure of a dam owned by Ameren.

[9] Efforts are being made to extend that trail from Pleasant Hill further into the center of the Kansas City metro area.

A "quad state" proposal would connect the Katy and other existing trails in Missouri, Kansas, Iowa, and Nebraska.

If the connection in St. Charles is destroyed or otherwise rendered unusable by rail (such as by natural disaster), the segment of the trail between St. Charles and Boonville would lose its railbanked status and ownership of the land would probably revert to its original owners from before the MKT Line was built.