The Antiquities Act of 1906 is an act that was passed by the United States Congress and signed into law by Theodore Roosevelt on June 8, 1906. This law gives the president of the United States the authority to, by presidential proclamation, create national monuments from federal lands to protect significant natural, cultural, or scientific features. The Act has been used more than a hundred times since its enactment.

In the United States, a national monument is a protected area that can be created from any land owned or controlled by the federal government by proclamation of the president of the United States or an act of Congress. National monuments protect a wide variety of natural and historic resources, including sites of geologic, marine, archaeological, and cultural importance. In contrast, national parks in the U.S. must be created by Congressional legislation. Some national monuments were first created by presidential action and later designated as national parks by congressional approval.