During these tough economic times the National Park Service (NPS) will waive entrance fees on the following days: April 17-25 (National Park Week), June 5-6 (National Trails Day), August 14-15, 2009. The National Park Service wants to reinforce that national parks are places for everyone to have fun, reconnect with nature and history, and build a sense of ownership and stewardship toward parks and the environment. These fee-free weekends will be in addition to our annual fee-free days on National Public Lands Day, Sept. 25, and Veterans Day, November 11.
For further information.
Source: U.S. Department of the Interior, National Park Service