Papahānaumokuākea Marine National Monument preserves one of the most untouched areas of coral reef in the world.
The main difference between national marine sanctuaries and marine national monuments is the designation process and the laws under which they are established. Sanctuaries are designated by the Secretary of Commerce, through NOAA, under the National Marine Sanctuaries Act (NMSA). The NMSA requires extensive public process, local community engagement, stakeholder involvement, and citizen participation, both prior to and following designation.
Monuments are designated by Presidential Proclamation, via the Antiquities Act of 1906. The Act is very simple, has changed little in more than a century, provides broad power to set aside public areas for protection, and requires no public process.
The NOS Office of National Marine Sanctuaries manages 13 national marine sanctuaries and one national marine monument. At more than 140,000 square miles (362,598 square kilometers), Papahānaumokuākea Marine National Monument is the largest protected area in the United States, stretching the length of the Northwestern Hawaiian Islands. The Monument, co-managed with the State of Hawai’i and the Department of the Interior, was designated on June 15, 2006 by President George W. Bush under Presidential Proclamation 8031.
Original article: What is a marine national monument?