The Library of Congress has numerous primary sources collections related to U.S. National Parks.
The Evolution of the Conservation Movement, 1850-1920
This collection documents the historical formation and cultural foundations of the movement to conserve and protect America's natural heritage, through books, pamphlets, government documents, manuscripts, prints, photographs, and motion picture footage drawn from the collections of the Library of Congress.
Historic American newspapers selected and contributed by state partners in the National Digital Newspaper Program.
This collection documents the history, cultural aspects and geological formations of areas that eventually became National Parks. The collection consists of approximately 200 maps dating from the 17th century to the present, including 25 maps of Yellowstone National Park
Search engines can be useful for locating specific primary source documents. If you use Google, enter the names of specific documents in quotation marks.
For broader searches, add primary source keyword terms, such as documents, primary sources, or papers to your search.