Interstate 55 begins in Chicago along Lake Shore Drive (US Route 41) and heads southwest along the former route of US Route 66, crossing the Mississippi River into St. Louis, Missouri. It passes along Joliet's western flank and connects to Normal, Bloomington, and Springfield before it reaches the St. Louis metroplex.
The exit list starts in the south, at St. Louis, and will proceed going northward, as is typical for odd-numbered Interstate highways. Interstate 55 crosses into Illinois from Missouri via the Poplar Street Bridge, which also carries Interstate 64 and US Route 40:
Exit 1 provides access to Illinois 3's southern leg toward Cahokia; the state route joins Interstate 55, Interstate 64, and US Route 40 to the north and east:
Exit 1A splits from the ramp to exit 1, and it provides access to Tudor Avenue and 13th Street in East Saint Louis:
Exit 2A provides access to Barack Obama Avenue, the Eads Bridge, and the (unmentioned) western end of Illinois 15:
Exit 2B is only accessible from the southbound lanes, but it provides access to the MLK Bridge:
Exit 11 is a fountain interchange accessing Illinois 157, to Collinsville and Edwardsville...
Exit 15A is for Illinois 159 south toward Collinsville...
Exit 15B is the second half of the cloverleaf, leading to Illinois 159 north toward Maryville...
Exit 17 is a trumpet interchange allowing US Route 40 to split from Interstates 55 and 70, for travelers seeking out St. Jacob or Highland, Illinois...
Exit 18 is a single-point interchange connecting to Illinois 162 and Troy...
Exit 20A sends Interstate 70 eastward toward Indianapolis on its own, finally independent of Interstate 55...
At the same interchange, Exit 20B connects to Interstate 270 west toward Kansas City:
Exit 23 accesses Illinois 143, taking travelers to Edwardsville or the town of Marine:
Exit 30 connects with Illinois 140, a road bringing people to Alton or Greenville:
Exit 33 connects to the north-south Illinois 4 from a diagonal northeastward Interstate 55, and Illinois 4 connects with Staunton and Lebanon:
Exit 37 links travelers to Livingston and New Douglas (even though we are not in Livingston or Douglas County):
Exit 41 provides access to the town of Staunton, on the east side of that town:
Exit 44 leads to Illinois 138, which connects to Mt. Olive and Benld:
Exit 52 is a partial cloverleaf interchange leading to Illinois 16, Litchfield, and Gillespie:
Exit 60 is a way to reach the eastern end of Illinois 108, which leads west to Carlinville: