Starved Rock State Park visitors will have to enter on Route 71 at the south entrance and park at the gravel overflow lot.
The main parking area and boat ramp by the Illinois River is closed because of projected floodwaters. The visitor center will remain open 9 a.m. to 4 p.m. Trails also remain open.
The Illinois River at La Salle is expected to crest at about 3.5 feet above flood stage 3 a.m. Wednesday, according to the National Weather Service Advanced Hydrologic Prediction Service.
The Illinois River at Ottawa crested at about 0.5 feet above flood stage, which causes flooding at Allen Park especially near the west boat ramp.