Illinois Route 151 is a short north-south route in western Jackson County. It runs from Illinois 3 to Illinois 4 in southwestern Illinois. The Mississippi River meanders from a southward flow to an eastern flow in this area, and Illinois 151 is situated just north of this easterly flowing segment of river.
The northern end of Illinois 151 is at Illinois 4 in Ava:
After traveling south for about 8 miles, Illinois 151 ends at Illinois 3.