Marine monuments and national marine sanctuaries are both types of marine protected areas. 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 NOAA or Congress and are managed by NOAA using 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.
The Office of National Marine Sanctuaries serves as the trustee for a network of underwater parks encompassing more than more than 600,000 square miles square miles of marine and Great Lakes waters from Washington state to the Florida Keys, and from Lake Huron to American Samoa. The network includes a system of 14 national marine sanctuaries and Papahānaumokuākea and Rose Atoll marine national monuments.