U.S. Federal Route 51 is the main north-south highway in Western Marion County. This runs on a expressway from the Marion/Jefferson/Washington County Line to Centralia. U.S. Rt. 51 passes through the following towns in Marion County. Centralia
Central City
Sandoval
Vernon
U.S. Rt. 51 is multi-plexed in Marion County. U.S. Rt. 50, at Sandoval.
U.S. Rt. 51 intersects the following highways in Marion County. Illinois State Route 161, at Centralia.
NB U.S. Rt. 51 near the Fayette/Marion County Line. SB U.S. Rt. 51 near Vernon. A junction marker on WB U.S. Rt. 50/NB U.S. Rt. 51. NB U.S. Rt. 51 near Central City. SB U.S. Rt. 51 south of Centralia. NB U.S. Rt. 51 south of Centralia.