The Act was intended to allow the president to set aside certain valuable public natural areas as park and conservation land. The 1906 act stated that it was intended for: "... the protection of objects of historic and scientific interest." These areas are given the title of "
national monuments." It also allows the president to reserve or accept private lands for that purpose. The aim is to protect all historic and prehistoric sites on United States federal lands and to prohibit excavation or destruction of these antiquities. With this act, this can be done much more quickly than going through the Congressional process of creating a
national park. The Act states that areas of the monuments are to be confined to the smallest area compatible with the proper care and management of the objects to be protected. Protection of sites can include restrictions on mining, logging, grazing, commercial fishing, and hunting; known as land withdrawals, these are typically described in the presidential proclamation establishing the monument. Some areas designated as national monuments have later been converted to or incorporated into national parks or
national historical parks. 28 of the
63 national parks include areas originally designated as national monuments. The first use of the Act protected a large geographic feature: President Theodore Roosevelt proclaimed
Devils Tower National Monument on September 24, 1906. President Roosevelt also used it to create the Grand Canyon National Monument (now
Grand Canyon National Park) and sixteen other sites. At ,
Papahānaumokuākea Marine National Monument is the largest protected area proclaimed. George W. Bush signed proclamation Proclamation 8031 to establish the monument in 2006, and President Barack Obama expanded its size in 2016. The smallest,
Father Millet Cross National Monument (now part of a state park), was a mere . For any excavation, the Act requires that a permit (Antiquities Permit) be obtained from the Secretary of the department which has jurisdiction over those lands. Presidents have historically tended to create more monuments during their second terms or
lame duck periods. ==Reduction of powers==