National monuments can either be established by Congress though legislation or by the president of the United States through the use of the Antiquities Act.

In the United States, there are two primary ways an area becomes a national monument. Under the Antiquities Act of 1906, the President of the United States has the authority to issue a proclamation to protect "objects of historic or scientific interest" located on federal lands. This allows for swift protection without needing a vote from lawmakers. Alternatively, Congress can create a national monument through the standard legislative process by passing a bill that the President then signs into law. While the President can create them, only Congress has the power to officially redesignate a national monument into a "National Park." Once established, these monuments are managed by various federal agencies, including the National Park Service (NPS), the Bureau of Land Management (BLM), or the U.S. Forest Service. The decision process often involves years of advocacy from local communities, scientists, and indigenous groups who seek to preserve the cultural or natural significance of a specific site.