List of National Monuments of The United States

The United States has 112 protected areas known as national monuments. The President of the United States can establish a national monument by executive order, and the United States Congress can by legislation. The Antiquities Act of 1906 authorized the president to proclaim "historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest" as national monuments. Concerns about protecting mostly prehistoric Indian ruins and artifacts—collectively termed antiquities—on western federal lands prompted the legislation. Its purpose was to allow the president to quickly preserve public land without waiting for legislation to pass through an unconcerned Congress. The ultimate goal was to protect all historic and prehistoric sites on U.S. federal lands.

President Theodore Roosevelt established the first national monument, Devils Tower in Wyoming, on September 24, 1906. He established eighteen national monuments, although only nine still retain that designation. Sixteen presidents have created national monuments since the program began; only Richard Nixon did not. Bill Clinton created the most monuments, nineteen, and expanded three others. Jimmy Carter protected vast parts of Alaska, proclaiming fifteen national monuments, some of which later were promoted to national parks. The most recent national monument designated by Presidential Proclamation was by Barack Obama on October 8, 2012 (César E. Chávez National Monument).

Twenty-seven states have national monuments, as do the District of Columbia, the Virgin Islands, American Samoa, the Minor Outlying Islands, and the Northern Mariana Islands. Arizona, with eighteen, has the largest number of national monuments, followed by New Mexico with twelve and California with eleven. Fifty-five national monuments protect places of natural significance, including ten geological sites, seven marine sites, and five volcanic sites. Twenty-two national monuments are associated with Native Americans. Twenty-four are other historical sites, including twelve forts.

Many national monuments are no longer designated as such. Some were changed to national parks or another status by Congress or the President, while others were transferred to state control or disbanded.