Entrance gates to the Grand Canyon remained unlocked Monday with no one collecting fees during the federal government shutdown.
Visitors were free to hike trails at the national park, stay in the campgrounds, and use river and backcountry permits they already had.
Concessionaries are keeping lodges, campgrounds, restaurants and retail shops open.
But anything run by the National Park Service, such as visitors centers and permit offices, was shut down. Campgrounds run by the agency had no one checking reservations.
Workers over the weekend posted signs saying that emergency services will be available but limited. Non-essential workers were furloughed.
The state of Arizona has donated money to clean restrooms, empty trash and plow roads, if needed.