Free America the Beautiful - National Parks and Recreational Land Pass - Access Pass - Free.

This link is for a lifetime pass for U.S. citizens or permanent resident with permanent disabilities. This pass provides access to, and use of, Federal recreation sites that charge an entrance or standard amenity. The pass provides 50% discount on some Expanded Amenity fees charged for facilities and services such as camping and swimming


http://www.nps.gov/fees_passes.htm