Papahānaumokuākea National Marine Sanctuary | Office of National Marine Sanctuaries

Sanctuary Designation

The designation of Papahānaumokuākea National Marine Sanctuary became effective on March 3, 2025. NOAA announced the effective date in this Federal Register notice on March 24, 2025.

Designated in 2025, Papahānaumokuākea National Marine Sanctuary is America's 18th national marine sanctuary, and is the largest in the National Marine Sanctuary System. The sanctuary encompasses 582,570 square miles of Pacific Ocean waters in Hawaiʻi, providing protection to nationally significant natural, cultural, and historical resources while bringing opportunities for research, community engagement, and education and outreach activities. The sanctuary is coextensive with the marine portions of Papahānaumokuākea Marine National Monument, and is managed in partnership with the monument co-trustees.

Boundry map of Papahānaumokuākea National Marine Sanctuary

Map of Papahānaumokuākea National Marine Sanctuary showing sanctuary boundaries, which encompasses 582,570 square miles of Pacific Ocean waters in Hawai’i. Image: NOAA

National Marine Sanctuary System

Safeguarding America's Premier Marine Places

From Washington state to the Gulf of America and from the Great Lakes to the Pacific Islands, the National Marine Sanctuary System protects 18 underwater parks spanning over 629,000 square miles of ocean and Great Lakes waters. By investing in innovative solutions, we strengthen these iconic places to address 21st-century challenges while supporting America's commerce and tourism. These unique locations inspire people to visit, value, and steward our nation’s iconic ocean and Great Lakes waters.