The Wilderness Act set up the National Wilderness Preservation System.  Passed by the U.S. Congress in 1964, this law has led to the designation of over 95 million acres of land as wilderness.  In the Act, wilderness is defined as land left undisturbed by humans.  The Act is intended to preserve land in its natural condition for the good of both the environment and humanity.

In the early 1900s, preservationists such as Aldo Leopold had pushed for certain areas to be created in which there would be no roads or other human additions.  The Forest Service soon developed a policy for the designation of such areas.  A regulation issued in 1929 gave the Chief of the Forest Service the power to set aside "primitive" areas.  However, these areas allowed wood and water resources to continue to be developed.

In the 1930s, the Forest Service became concerned that its primitive areas would be taken over by the National Park Service.  This gave the Forest Service reason to designate more wilderness for several reasons:  to demonstrate the Service's protection capabilities, to preserve resources until they were needed, and to put various Forest Service Lands into good use for recreation, research, and preservation.  These new areas would be called "wilderness areas" if they were over 100,000 acres and "wild areas" if they were between 5,000 and 100,000 acres.  The first would be established by the Secretary of Agriculture and the later by the Chief of the Forest Service.  "Recreation" areas were also created and allowed to develop under the Chief's instruction.

Need of legal protection of these lands led to the introduction of various wilderness bills in Congress.  After 65 such attempts, the Wilderness Act was passed.  Many compromises had been made regarding the use of designated land: motorboat and aircraft use was permitted; fires, insects and diseases could be controlled; grazing was permitted; and water developments could take place if approved by the President.  The original act set aside 9.1 acres wilderness.

By 1992, a total of 95.3 million acres of wilderness had been created. Out of this, 386 areas of 34 million acres are managed by the Forest Service, 41 areas of 39.1 million acres by the National Park Service, 75 areas of 20.6 million acres by the Fish and Wildlife Service, and 66 areas of 1.6 million acres by the Bureau of Land Management.

The text of the law