April 19 - 27 is National Park Week in the U.S. All parks are free to enter Saturday and Sunday , April 19 - 27 . Entry and concession fees still apply . What 's the best national park in the world ? Take your photos .
April 19-27 is National Park Week in the U.S. All parks are free to enter Saturday and Sunday , April 19-20 . Campground and concession fees still apply . What 's the best national park in the world ? Share your photos .