Illinois Route 143 is an east-west highway in southwestern Illinois, extending from Alton to points east. It runs only from Madison County to southern Bond County, where it ends at Illinois 127.
From west to east, Illinois 143 starts (in the west) in Alton at US Route 67, just north of that route's crossing of the Mississippi River...
From west to east, Illinois 143 starts (in the west) in Alton at US Route 67, just north of that route's crossing of the Mississippi River...
A block to the east of the western terminus, Illinois 143 meets the western end of Illinois 140...
Leaving Alton and entering Wood River, Illinois 143 encounters Illinois 3...
After about another mile, Illinois 143 crossing Illinois 111...
Entering Edwardsville, Illinois 159 joins Illinois 143 eastward from the north...
At an intersection in Edwardsville, Illinois 157 comes from the southwest to join Illinois 143 at the same point where Illinois 159 breaks its concurrency to continue south all on its own...
Just to the east, as Illinois 143 is on its way out of Edwardsville, Illinois 157 splits off to continue north...
A short distance east of Edwardsville, Illinois 143 meets a diamond interchange with Interstate 55...
Illinois 143 crosses Illinois 4 at a town called Marine:
Between Marine and Highland, Illinois 143 meets Interstate 70 at a diamond interchange...
Illinois 143, now on the south side of Interstate 70, meets US Route 40, forming a concurrency that continues east in Highland...
Also in Highland, Illinois 160 comes from the north to join Illinois 143 and US Route 40 eastward...
After a short triplicate of a concurrency, Illinois 160 continues south, independently, to pass through the heart of Highland, and Illinois 143 and US Route 40 continue east...
Approximately two miles later, Illinois 143 splits from US Route 40 to head more directly east...
Near the unincorporated place of Beaver Creek, Illinois 143 ends at Illinois 127...