In Illinois, US Route 50 runs east-west across the southern part of the state. It enters the state of Illinois crossing the Mississippi River just south of St. Louis, and then it runs along a corridor between Interstates 64 and 70, departing from Illinois into Vincennes, Indiana.
US Route 50's western entrance into Illinois is along the bridge carrying Interstate 255 around the south side of the St. Louis metropolitan area:
US Route 50's western entrance into Illinois is along the bridge carrying Interstate 255 around the south side of the St. Louis metropolitan area:
Interstate 255's exit number 20 sends US Route 50 to head eastward, onto a new concurrency with Interstate 64:
Exit 19B from Interstate 64 occurs at a cloverleaf interchange, where O'Fallon meets Shiloh, and where the northern end of Illinois 158 meets the start of US Route 50's existence as an independent surface highway:
In Lebanon, US Route 50 joins Illinois 4 north for about a mile...
In downtown Lebanon, US Route 50 splits from Illinois 4 to head east:
US Route 50 has a bit of an expressway section, and it creates a diamond interchange with Illinois 160 in Trenton, Illinois...
In Carlyle, US Route 50 joins Illinois 127 south:
After a single mile, the concurrency ends with US Route 50 turning from Illinois 127 to go east again...
At Sandoval, US Route 50 joins US Route 51 for a short distance:
Then US Route 50 splits from US Route 51 to resume heading easterly:
As US Route 50 approaches Salem, it meets an interchange with Interstate 57...
In Salem, US Route 50 crosses Illinois 37:
At Flora, US Route 45 joins from the north to follow US Route 50 east for a while...
After about four miles, US Route 45 splits from US Route 50 to head southerly again...
At the town of Noble, US Route 50 forks into the western start of Illinois 250...
At Olney, US Route 50 crosses Illinois 130, where Illinois 250 comes from the north to join US Route 50 east:
US Route 50 then sends Illinois 250 south into Sumner...
A partial interchange splits US Route 50 into a bypass expressway and a business alignment for access to Lawrenceville, Illinois...
That US Route 50 bypass has an interchange with Illinois 1, alongside Lawrenceville...
Another partial interchange allows the business alignment of US Route 50 to rejoin the main route...
US Route 50 meets the southern end of Illinois 33 at a full-access interchange...
Shortly after meeting Illinois 33, US Route 50 crosses the Wabash River, out of Illinois and into Vincennes, Indiana...
