The Ohio Department of Natural Resources says visitors can camp for free at 54 campgrounds on April 18. The agency's director says the free stay gives people a chance to explore new parts of the state and discover Ohio's parks. Interested campers can make a reservation for the night by calling the parks' reservation center at 1-866-644-6727. The state says walk-ins also are welcome, but space is limited. The promotion isn't available at Jackson Lake State Park or Strouds Run State Park because they are concession-operated campgrounds