All national parks that charge an entrance fee will offer free admission to everyone in celebration of National Public Lands Day — which occurs every year on the fourth Saturday of September. It is one of the six days in a calendar year when the National Park Service waives any and all entrance fees.

National Public Lands Day is Saturday, a day honored by the National Environmental Education Foundation and National Park Service and other federal agencies.

National Public Lands Day is an annual event and has been the nation's largest single-day volunteer effort, according to the National Parks Service.