Illinois Route 49 acts as the second longitudinal (north-south) route west of the Indiana border in east-central Illinois. It's largely desolate and very rural, but it runs for a considerable distance across the entire length of what I would consider "east-central Illinois".
Illinois 49's northern end is where US Route 45 and US Route 52 split about fifteen miles south of Kankakee. At this junction, US Route 52 turns easterly and US Route 45 turns westerly, and proceeding straight south gives you the birth of Illinois 49:
Illinois 49 continues south through Iroquois County, and it crosses US Route 24 at Crescent City, Illinois:
At Rankin, Illinois 49 meets Illinois 9 at a 4-way intersection: