It runs from IL 113 in downtown Braidwood north to Interstate 55 (I-55).

The highway is an undivided two-lane surface road for its entire length.

It heads northeast as Washington Street, parallel to the Union Pacific Railroad tracks and IL 53.

In 1995, a section of the highway south of Braidwood was closed to through traffic when a deteriorated bowstring arch bridge over a railroad line was deemed too expensive to repair.

[2] On October 1, 2011, the deteriorated overpass at the interchange with I-55 was closed and removed, as was the previous U-turn ramp approximately 0.25 miles (0.40 km) north of the interchange so vehicles from IL 129 could access southbound I-55.