From the National Parks Service:
Searchable E-book: U.S. National Parks List
Search a database of over 400 National Parks from the National Parks Service. The U.S. National Park Service cares for and protects national parks. People from all around the world visit national parks.
There are nearly 400 natural, cultural and recreational sites across the nation. This eBook provides name, location, contact information and a short description for over 400 National Parks, monuments, historical sites, and more.