The National Park Service is waiving admission fees to all of the 397 National Parks in the United States during National Park Week.
National Park Week runs April 21 - 29. During that time, you can get into Big Bend, Fort Davis, the Amistad NRA, or any of Texas' 13 national parks, for free.
The week serves as an incentive for Americans to embrace the public lands.
If you can't make it out during National Park Week, the park service will also waive entrance fees on June 9.