This national conservation organization focuses on protecting national parks, forests, wildlife refuges, seashores, and recreation areas and lands administered by the Interior Department's Bureau of Land Management (BLM), which total almost one million mi² (2.6 million km²). The Society has played a leading role on many environmental issues in the last half of the century involving public lands, including protecting 84 million acres (34 million ha) of land as wilderness areas since 1964.

The Society was founded in 1935 by naturalist Aldo Leopold and other conservationists, in part to formulate and promote a land ethic, a conviction that land is a precious resource "to be cherished and used wisely as an inheritance." One of the Society's proudest accomplishments was the passage of the landmark Wilderness Act (1964), which recognized for the first time that the nation's wild areas had a value and integrity that was worthy of protection and should remain places...