Missouri Route 240

Route 240 begins its journey east in Marshall at U.S. Route 65, concurrent with southbound Business Loop 65. Less than ½ mile down the road, Route 240 dumps Business Loop 65 and picks up southbound Route 41. Route 41 leaves a few miles east of Marshall, leaving Route 240 to head on its own. Route 240 heads north-northeast through gently rolling hills to Slater, where Route turns east. The highway then passes through Gilliam, crosses the Missouri River, then enters Glasgow. At the Glasgow end of the bridge, Route 240 becomes concurrent with the southbound directions of Route 5 and Route 87, and at the same time gains a business loop. As the highway exits Glasgow, Routes 5 and 240 turn off of Route 87 and head east-northeast (despite being signed as a southbound direction) until meeting the other end of Business Loop 240, after which the duplex turns east. The duplex later turns south-south east and meets the southern terminus of Route 3. North of Fayette, Route 240 turns off of Route 5, but still heads in the southeasterly direction as it passes through Downtown Fayette. South of the city, Route 240 serves as the western end of Route 124. Route 240 then becomes hillier until it meets U.S. Route 40, where it flattens out and meets Alternate Route 240, which provides easier access from eastbound Route 240 to westbound Route 40, and vice versa (see below).

Business Loop 240 runs entirely on the old routing of Route 240. It begins at the Glasgow end of the bridge over the Missouri River. It heads north concurrent with Route 5 through Downtown Glasgow. After passing through downtown, Route 5 leaves, and Business 240 runs eastward to the new routing of Routes 5 and 240.

Alternate Route 240 in rural Howard County is technically a spur route that provides easy access from eastbound Route 240 to westbound U.S. Route 40, and vice versa, utilizing an old alignment of U.S. Route 40. The route runs northeast from U.S. Route 40 at the southeastern edge of the Davidsdale Conservation Area, then passes through some farmland. After running along the northwestern edge of a small pond, it intersects Howard County Road 435A, and immediately the shared intersection of Howard County Roads 442 and 435. Before reaching its northeastern terminus, the road curves east, where a connecting road leads to westbound Route 240, while the existing road curves to the southeast and ends at eastbound Route 240.

Route 240 Spur is a spur route from US 40/MO 240 that runs towards Rocheport, Missouri. Though cardinal direction signs read "East," it actually runs south from its parent route, taking the Lewis and Clark Trail with it. The road then curves to the southeast where it has a wye intersection with Howard County Road 440. Spur Route 240 officially enters Rocheport, just before crossing a bridge over Moniteau Creek where it also crosses the Howard-Boone County Line, then ends at Route BB (Third Street), which takes the Lewis and Clark Trail with it, while Spur Route 240 continues south as Central Avenue which leads to a portion of the Katy Trail State Park.