Illinois officials say Memorial Day visitors to Starved Rock State Park should monitor social media for reports on traffic delays and parking closures.
Department of Natural Resources officials say large crowds are expected at the recreation area near Utica in LaSalle County.
Illinois River flooding closed some parking this spring. But officials say all lots should be open for Memorial Day weekend.
Rafael Gutierrez is chief of the state agency's office of law enforcement. He says motorists should be patient and follow directions from conservation police and park staff around Starved Rock this weekend.
Police will enforce Starved Rock rules. They include no alcohol anywhere in the park until June 1; no off-trail hiking or trail-walking after dark; no rock- or cliff-climbing; no swimming; no defacing sandstone walls or littering.