The Conservation Collection was established in 1960 by author and conservationist Arthur H. Carhart, in cooperation with Denver City Librarian John Eastlick. Comprised of organizational records and personal papers, the Conservation Collection documents the history of the environmental movement in the United States from the early 20th century to the present.
Organizations such as The Wilderness Society, The Student Conservation Association, American Farmland Trust and The Nature Conservancy have designated the Denver Public Library as the official repository for their records. Some of the individuals who have contributed papers, memos and writings include Ira Gabrielson, first director of the U.S. Fish and Wildlife Service; Howard Zahniser, Executive Secretary, The Wilderness Society; Enos Mills, author and lecturer, best remembered as the father of the Rocky Mountain National Park; and Velma (Wild Horse Annie) Johnston, who worked for federal legislation to protect wild horses and burros.