Illinois Route 351 is a short route giving LaSalle, Illinois, a primary north-south travel corridor through town. While Illinois 251 is an old alignment of U.S. Route 51, Illinois 351 is yet another old version of that old alignment. In the vicinity of LaSalle, Peru, and Interstate 80, U.S. Route 51 now runs concurrently with Interstate 39 on the east side of these twin cities. Illinois 251, the more recent surface route formerly carrying U.S. Route 51, runs through Peru, the westerly of the two cities. Illinois 351 begins at Illinois 251 south of LaSalle, where Illinois 71 crosses Illinois 251; then, Illinois 351 continues north, breaks away from Illinois 71, runs through LaSalle, and ends at a trumpet interchange with Interstate 80. All of Illinois 351 is in western LaSalle County.
From south to north, Illinois 351 passes through the following junctions:
Illinois 351's southern start is at the 4-way junction where Illinois 71 crosses Illinois 251, south of Oglesby.
From south to north, Illinois 351 passes through the following junctions:
Illinois 351's southern start is at the 4-way junction where Illinois 71 crosses Illinois 251, south of Oglesby.
At the junction of Illinois 71 and Illinois 251, Illinois 71 curves from an easterly direction to a northerly direction, duplexed with the southern section of Illinois 351. After heading northerly through Oglesby, one of the gateway towns to the Starved Rock area, Illinois 351 splits toward the west while Illinois 71 turns back toward the east:
After crossing the Illinois River, Illinois 351 follows the main drag north through LaSalle, meeting US Route 6, which joins from the west to form a short concurrency:
The concurrency with US Route 6 through LaSalle lasts for only two blocks:
As Illinois 351 exits the urbanized section of LaSalle, Illinois, the route finally meets its end at Interstate 80.
