^Westbound trailblazer as Illinois 157 splits from Illinois 163 in the Cahokia Heights area, February 2023.
Illinois Route 157 is mainly a north-south route in the Metro-East, with a small "J"-shaped hook at the southern end. The northern end is in the small town of Hamel at Illinois 140, just seconds west of Interstate 55. It heads south-southwesterly overall, passing through Edwardsville, Collinsville, Caseyville, and Centreville. At Centreville, Illinois 157 bends northwesterly to form the hook of the "J"-shape. The end of the hook, and the end of the route, is at Illinois 3 in Cahokia Heights.
Illinois 157's northern end is at Illinois 140, just west of Interstate 55...
Illinois 157's northern end is at Illinois 140, just west of Interstate 55...
Illinois 157 joins Illinois 143 west as it enters Edwardsville...
In inner Edwardsville, Illinois 157 continues west at a 4-way intersection where it crosses Illinois 159, and Illinois 143 turns right to join Illinois 159 northward...
Illinois 157 soon straightens out to head more southwesterly again, and has an interchange with Interstate 270...
A bit farther south, Illinois 162 comes from the west and joins Illinois 157 south to cross a creek:
After one of the shortest roadway concurrencies in existence, Illinois 162 continues east immediately after crossing the creek:
At a lopsided folded diamond (fountain) interchange, Illinois 157 is provided access to the Interstate 55/70 concurrency...
After passing through Caseyville, Illinois 157 meets Interstate 64 at another folded diamond (fountain) interchange...
At yet another interchange where Illinois 157 is treated as the surface road, the Illinois 15 expressway interacts with Illinois 157...
Soon after, Illinois 157 reaches a roundabout where it joins Illinois 13 westward...
Illinois 13 promptly ends at Illinois 163, which Illinois 157 joins southbound...
Illinois 157 and Illinois 163 share a short concurrency, then Illinois 163 splits off to head south, sending Illinois 157 in more of a westerly direction...
Illinois 157 is now curving northwesterly, giving the route its "J" shape, and it crosses Interstate 255 with an interchange...
Illinois 157 then comes to an end in Cahokia Heights, at Illinois 3, facing northwesterly...