Illinois Route 127 is a long north-south route in southwestern Illinois. It runs from a point halfway between Springfield and St. Louis, south almost all the way to Cairo. It connects seven county seats in a row, and that's part of what makes it an important route through rural southwestern Illinois.
A couple blocks west of that T-intersection, Illinois 127 splits off to continue south, whereas Illinois 149 continues west into downtown Murphysboro. This and the previous two junctions are in Murphysboro, the sixth of the seven county seats connected by Illinois 127:
After passing through Alto Pass and the heart of the Shawnee Hills Wine Trail, Illinois 127 reaches Illinois 146, and turns easterly to follow that route into Jonesboro:
At a long-standing roundabout in Jonesboro, the seventh and final county seat traversed by Illinois 127, the route splits from Illinois 146 to resume heading southward:
Illinois 127 finally reaches its southern end at Illinois 3 in Alexander County, where travelers can continue south to Cairo (yet another county seat) or to Interstate 57.