Fee Free Day in all National Parks

National parks are America’s Best Idea, and there are more than 400 parks available to everyone, every day. The fee-free days provide a great opportunity to visit a new place or an old favorite, especially one of the 120 national parks that normally charge an entrance fee. The others are free all of the time. Plan your visit and enjoy our country’s history and nature. The fee waiver includes entrance fees, commercial tour fees, and transportation entrance fees. Other fees such as reservation, camping, tours, concession and fees collected by third parties are not included unless stated otherwise.

https://www.nps.gov/planyourvisit/fee-free-parks.htm