"Conserve the natural and historic objects in such manner as will leave them unimpaired for the enjoyment of future generations..."
In the United States, the differences between a national park and a national monument are slim. Both need be nothing more than a strip of land which has been set aside for public use. An act of congress is required to create a national park, the Yellowstone National Park Act of 1872 being the first - congress set aside the Yellowstone watershed for "for the benefit and enjoyment of the people." The passage of the Antiquities Act in 1906 gave the president the power to designate historical landmarks and monuments which were already on federal land. In 1916 the National Park Service Organic Act created a National Park Service to "promote and regulate the use of the Federal areas known as national parks, monuments, and reservations..."
The national park system is currently made up of 384 areas over 83 million acres of land - from a park less than a fifth of an acre in Pennsylvania to a
13 million acre preserve in Alaska. The service is split into seven divisions with field offices in Alaska, Nebraska, Colorado, California, Pennsylvania, Georgia and
Making the call on titles has been difficult: if you are familiar with any of these parks or monuments please let me know if I've chosen an inappropriate title. Death Valley is rarely referred to as "Death Valley National Park" while Rocky Mountain National Park is rarely referred to as "Rocky Mountain." Throw me a bone.
U.S. National Parks, Monuments and Historic Sites: