US Route 150 follows the Interstate 74 corridor in Illinois, deviating at the last minute from that corridor to cut southerly and easterly toward Terre Haute, Indiana. US Route 150 starts on the southern outskirts of the Quad Cities area, running almost due-south to Galesburg, then turning southeasterly through Peoria, Bloomington, and Champaign-Urbana, before turning south from Danville toward Terre Haute.
The northwestern end of US Route 150 is at US Route 6 just south of Moline:
US Route 150 runs southerly here, meeting the western end of Illinois 81 three miles west of Andover:
At the small town of Alpha, Illinois 17 comes from the west to join US Route 150 south:
After about a mile and a half, Illinois 17 splits from US Route 150 to resume going easterly:
Next, US Route 150 enters Galesburg, meeting a cloverleaf interchange with the US Route 34 freeway:
After passing through Galesburg and Knoxville, US Route 150 meets the northern end of Illinois 97 and subsequently crosses a diamond interchange with Interstate 74:
Near Williamsfield, US Route 150 meets the southern end of Illinois 180:
Near the tiny town of Laura, US Route 150 joins Illinois 78 south:
US Route 150 southeasterly away from a deviating Illinois 78 toward the town of Brimfield; continuing a tiny distance south from this junction will lead travelers to an interchange accessing Interstate 74:
As US Route 150 enters Peoria, it meets the southern end of Illinois 91:
The very next block takes US Route 150 to an interchange with the Illinois 6 freeway:
Farther into Peoria, US Route 150 bends from southeasterly to easterly, near a point where Interstate 74 bends from easterly to southeasterly, and the two routes are joined by a connector meeting each route at a trumpet interchange:
Now in the thick of Peoria, US Route 150 crosses Illinois 40:
As US Route 150 is ramping up to cross the Illinois River out of Peoria, Illinois 29 passes underneath, and the two routes are joined by a fountain interchange:
On the north end of East Peoria, US Route 150 uses a fully-directional interchange to join Illinois 116 south, as US Route 24 comes from the east to also join Illinois 116 south:
As US Route 150 approaches Bloomington, it dives southward across Interstate 74 once again, meeting a diamond interchange of ramps to that freeway...
US Route 150 joins Illinois 9 east into the heart of Bloomington:
US Route 150 and Illinois 9 meet a partial cloverleaf interchange with Interstates 55 and 74 running concurrently with US Route 51:
US Route 150 and Illinois 9 continue concurrently into downtown Bloomington, where they split into a pair of one-way streets that each intersect the pair of one-way streets carrying Business US Route 51:
While still operating as a pair of one-way streets, Illinois 9 continues east through the rest of Bloomington, splitting with US Route 150, which follows a single road southeastward:
US Route 150 intersects Business Loop 55 on the southeast side of Bloomington, before it leaves town...
After passing through the town of LeRoy, a southeasterly US Route 150 crosses US Route 136:
As US Route 150 approaches Danville, it meets Interstate 74 once again, at an interchange...
In Danville, US Route 150 meets a 4-way junction with Illinois 1, which it joins southerly; meanwhile, US Route 136 arrives from the north on Illinois 1 and turns easterly, ricocheting off of US Route 150...
In Paris, US Route 150 and Illinois 1 head together down a pair of one-way streets, meeting a junction where US Route 150 turns easterly, and the western leg of the junction forms the eastern beginning of both Illinois 16 and Illinois 133:
US Route 150 heads east into Indiana, eventually turning southeasterly into Terre Haute, Indiana...