The Papahānaumokuākea Marine National Monument (pronounced [ˈpɐpəˈhaːnɐwˈmokuwaːˈkɛjə]; PMNM) is a U.S. national monument listed as a World Heritage Site. It covers 582,578 square miles (1.5 million km²) of ocean water, including ten islands and atolls in the Northwestern Hawaiian Islands. President George W. Bush created the monument in 2006, starting with an area of 140,000 square miles (360,000 km²). In 2016, President Barack Obama expanded the monument, increasing its size more than four times by extending its borders to the edge of the exclusive economic zone, making it one of the largest protected areas in the world.

The monument is home to more than 7,000 marine species. One quarter of these species are found only in the Hawaiian Islands, with some living only within the monument. Less than 5.8 square miles (15 km²) of land is above sea level, but this area is important for many land animals. The monument also includes ancient sites that are meaningful to Native Hawaiians. Deeper waters hold interest for historians because they contain shipwrecks, old planes, and remains from battles during World War II. As a protected area, the monument does not allow commercial fishing. In 2025, President Joe Biden named the marine areas of the monument the Papahānaumokuākea National Marine Sanctuary.

Geography

The Monument covers a large part of the Pacific Ocean, including ocean waters, more than 30 underwater banks and mountains, reefs, and ten islands and atolls in the Northwestern Hawaiian Islands. The boundary of the Monument starts offshore near the island of Nīhoa in the southeast, east of 163° W, close to the island of Niʻihau, which is just northwest of Kauaʻi. From there, the Monument’s boundary stretches 1,200 miles northwest to Kure Atoll.

The marine boundary extends seaward to the edge of the exclusive economic zone (EEZ) for areas west of 163° W longitude. This boundary beyond Kure Atoll crosses the International Date Line, creating a continuous protected area across the antimeridian. The total protected area covers about 582,578 square miles (1,508,870 km²). This area is larger than all of America’s national parks combined and is nearly the same size as the Gulf of Mexico.

Approximately 132,000 square miles (340,000 km²) of the Monument is part of the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve, established in 2000. The Monument also includes the Midway Atoll National Wildlife Refuge (590,991.50 acres or 2,391.7 km²), the Battle of Midway National Memorial, the Hawaii State Seabird Sanctuary at Kure Atoll, and the Northwestern Hawaiian Islands State Marine Refuge.

All islands in the Monument are part of the state of Hawaii, except Midway Atoll, which belongs to the United States Minor Outlying Islands. Henderson Field, a public airport on Midway Atoll, provides access to the Monument. Until the 2010s, French Frigate Shoals Airport on Tern Island had a runway. Though not officially closed, the runway is now inactive. The Fish and Wildlife Service’s field station on Tern Island was abandoned in 2012 after a severe storm damaged its buildings. Hurricane Walaka destroyed East Island in the shoals in 2018, but the island has recently started to recover.

Administration

The Monument is managed by four groups that share responsibility: the Department of Commerce, the Department of the Interior, the State of Hawai‘i, and the Office of Hawaiian Affairs (OHA).

The marine areas are managed by the official in charge of the Department of Commerce and the National Oceanic and Atmospheric Administration (NOAA). The Midway Atoll National Wildlife Refuge, the Battle of Midway National Memorial, and the Hawaiian Islands National Wildlife Refuge are managed by the official in charge of the Department of the Interior and the U.S. Fish and Wildlife Service (FWS). The Northwestern Hawaiian Islands Marine Refuge and State Seabird Sanctuary at Kure Atoll are managed by the State of Hawai‘i and the Hawaii Department of Land and Natural Resources (DLNR). Activities related to Native Hawaiian interests, customs, rights, practices, and religious traditions are managed by the Office of Hawaiian Affairs (OHA).

Monument management is supported by a Senior Executive Board that creates policies. A seven-member management board also helps manage the Monument. This board includes representatives from the Office of National Marine Sanctuaries and National Marine Fisheries Service in NOAA; Ecological Services and Refuges in FWS; Aquatic Resources, Forestry, and Wildlife divisions in DLNR; and the Office of Hawaiian Affairs (OHA).

History

The Northwestern Hawaiian Islands (NWHI) are valued for their cultural and natural significance by Native Hawaiians. They believe the area shows a connection between nature and people, and that life begins there and returns after death. Archaeological remains have been found on Nīhoa and Mokumanamana in the region.

After the Hawaiian Islands were taken over by the United States and became a territory, the area was first protected by the federal government on February 3, 1909. To address the over-harvesting of seabirds and because the NWHI is an important nesting site for seabirds, U.S. President Theodore Roosevelt created the Hawaiian Islands Bird Reservation through Executive Order 1019 in 1909. President Franklin D. Roosevelt changed it into the Hawaiian Islands National Wildlife Refuge in 1940. Over time, protections were expanded, leading to the creation of Midway Atoll National Wildlife Refuge in 1988 and the Kure Atoll State Wildlife Sanctuary in 1993.

President Bill Clinton established the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve on December 4, 2000, with Executive Order 13178. This order started a process to make the NWHI waters a National Marine Sanctuary. In 2005, Hawaii’s governor, Linda Lingle, declared parts of the Monument a state marine refuge.

President George W. Bush and his wife watched a documentary film called Voyage to Kure at the White House in April 2006 with its director, Jean-Michel Cousteau. Inspired by the film’s depiction of the area’s wildlife, Bush signed Proclamation 8031 on June 15, 2006, designating the NWHI waters a National Monument under the 1906 Antiquities Act. This action skipped the usual process of public consultation and occurred just before a draft environmental impact statement for a proposed National Marine Sanctuary was to be released. This was the second time Bush used the Antiquities Act, following the creation of the African Burial Ground National Monument in 2006.

A process to involve stakeholders in planning and managing a marine protected area (MPA) had taken five years, but the sudden designation of the NWHI as a National Monument, not a Sanctuary, provided immediate and stronger protection. This protection can only be changed by legislation.

President Bush updated Proclamation 8031 with Proclamation 8112, renaming the Monument “Papahānaumokuākea” on February 28, 2007. The name refers to a Hawaiian creation story and includes four words: Papahānaumoku, a goddess and Earth Mother; hanau, meaning “to give birth”; moku, meaning “islands”; and akea, meaning “the expanse of the islands.” The name was translated by Hawaiian hula teacher Pualani Kanakaʻole Kanahele as “the deity of our ancestors who extends to the Northwestern Hawaiian Islands, the great expanse she gave birth to.”

Bush announced plans to request that the Monument be designated a Particularly Sensitive Sea Area (PSSA) on May 15, 2007. This would warn sailors to be cautious in the area’s ecologically important waters. In October 2007, the International Maritime Organization’s Marine Environmental Protection Committee named the Monument a PSSA.

Co-trustees applied for the Monument to be considered for World Heritage Site status in 2007. In 2008, the U.S. added the Monument to its list of potential World Heritage Sites, along with Mount Vernon. After a review, the Monument was officially nominated to UNESCO in 2009. It was accepted in 2010 as “Papahānaumokuākea” at the 34th Session of the World Heritage Committee in Brasília.

President Barack Obama expanded the Monument’s area more than four times to cover the entire exclusive economic zone (EEZ) by signing Proclamation 9478 on August 26, 2016. The Monument grew from 139,797 square miles (362,073 km²) to 582,578 square miles (1,508,870 km²), extending west to −163° longitude and protecting ocean waters up to 200 nautical miles. At that time, it became the world’s largest marine protected area.

During the first Trump administration, Interior Secretary Ryan Zinke reviewed the Monument’s status.

The Biden administration proposed designating the Monument’s marine environment as a national marine sanctuary in November 2021. President Joe Biden finalized the expansion of the Monument’s protected areas as part of his “America the Beautiful” campaign. These areas, from the shore of each island or atoll to 200 nautical miles offshore, became the Papahānaumokuākea National Marine Sanctuary, the 18th national marine sanctuary in the United States, on January 15, 2025.

In 2025, the Department of Government Efficiency (DOGE), acting under the Trump administration, fired thousands of scientists, some of whom managed the Monument. At the same time, the Federal Aviation Administration (FAA) allowed SpaceX to use an area within 50 miles of the Monument as a containment zone for space debris from the Starship launch vehicle. In April 2025, Trump issued Executive Order 10918, “Unleashing American Commercial Fishing in the Pacific,” authorizing the Western Pacific Regional Fishery Management Council to allow commercial fishing in the Monument. This action was strongly opposed by scientists, conservationists, and Native Hawaiians.

Ecology

The Monument protects and supports 70% of the coral reefs in the United States, covering about 3.5 million acres. It is home to more than 7,000 marine species, and one quarter of these species are found only in the Monument. The small areas of land in the Monument support a variety of plants, land birds, and invertebrates that are found only there. In addition to these native species, 21 seabird and four migratory shorebird species live in the area.

At least 27 types of plants that are found only in the Monument grow there. Five of these plants are endangered and are only known and managed in the area: a species of Laysan agrimony sandbur (Cenchrus agrimonioides var. laysanensis, possibly extinct), Hawaiʻi chaff flower (possibly extinct), Amaranthus brownii (possibly extinct), Nīhoa carnation, and a species of Laysan sedge (Cyperus pennatiformis var. bryanii). Another 22 types of plants that are found only in the Hawaiian Archipelago live in the Monument. Four of these plants are endangered, and two are managed with their main populations in the Monument: a species of burr cucumber (Sicyos maximowiczii) and the endangered Pritchardia palm tree. Endemic invertebrates include the Nīhoa conehead katydid, the Nihoa giant tree cricket, and the Nīhoa trapdoor spider.

Four types of land birds that are found only in the Monument are endangered or threatened: the Nihoa Millerbird, Nihoa Finch, Laysan duck, and Laysan finch. Other important species include the endangered hawksbill sea turtle and the threatened green sea turtle, of which 95% rely on the French Frigate Shoals for nesting and breeding; the endangered Hawaiian monk seal; and seabirds such as the Laysan albatross.

In 2010, an expedition to Kure Atoll sent divers to a depth of 250 feet (76 m), where they found new coral and other animals. The Waikiki Aquarium cultured the new coral species. In 2015, a scientific team discovered one of the largest sponges in the world in the Monument. They used a remotely-operated vehicle to measure the sponge’s size, which was about the size of a small mini-van (3.5 × 2 × 1.5 meters). The team identified the sponge as a member of the Rossellidae family. Its age is unknown, but it is likely hundreds or even thousands of years old. In 2019, scientists found a type of seaweed that was harming large areas of coral.

• Benthic communities
• Bubblegum coral
• Red pencil urchin

• Fishes
• Hawaiian squirrelfish at French Frigate Shoals
• Pearl and Hermes Atoll: red tail wrasse, Thompson's anthias, Potter's angelfish, Hawaiian squirrelfish, chocolate-dip chromis, masked angelfish, and bluestripe butterflyfish
• School of sea chubs
• Obama's basslet
• Bigeye emperor
• Titan scorpionfish

• Marine turtles
• Green sea turtle
• Sea turtles basking
• Baby green sea turtles

• Avifauna
• Red-footed boobies nesting
• Laysan duck with ducklings
• Hawaiian gallinule
• Laysan albatross at Midway Atoll, Sand Island
• Laysan Finch on guano pile
• Nihoa finch
• Green sea turtles and masked boobies
• Laysan albatross mother and chick
• Nihoa millerbird

• Marine mammals
• Hawaiian monk seals on Midway Atoll
• Spinner dolphins
• Bryde's whale
• Hawaiian monk seals

Commercial fishing ban

Commercial fishing stopped in 2010 when the Monument received strong conservation rules. These rules allow exceptions for traditional Native Hawaiian uses and limited tourism. The NWHI bottomfish fishery was once limited to eight boats, each no longer than 60 feet (18 meters). This fishery provided about half of the bottomfish caught in Hawaii at that time.

According to the Pew Charitable Trusts, lobster populations have not recovered from heavy fishing in the 1980s and 1990s. Remaining fisheries are overfished. In 2008, the National Marine Fisheries Service (NMFS) reported that many species’ populations have not fully recovered from a major change in the oceanic ecosystem in the North Pacific during the late 1980s and early 1990s. This change reduced numbers of important species, including spiny lobster, seabirds, and Hawaiian monk seals.

A 2022 study found that the Monument’s protective status helped two fish populations recover. The protected areas acted like a tuna nursery, increasing fish catches outside the Monument’s boundaries. Researchers noted that yellowfin tuna catches rose by 54% between 2016 and 2019, while bigeye tuna catches increased by 12%. The greatest increases occurred 115 to 230 miles from the Monument’s edges.

Maritime history

The area of the Monument contains more than 80 shipwrecks and hundreds of underwater aircraft. Divers discovered the wreck of the USNS Mission San Miguel (T-AO-129) inside the Monument in 2015. The ship sank there on October 8, 1957, after running aground on Maro Reef while traveling at full speed and carrying heavy weight. The Battle of Midway National Memorial is also part of the Monument. The wreck of the Imperial Japanese Navy aircraft carrier Akagi, which sank during World War II in the Battle of Midway on June 4, 1942, was found within the Monument by the research ship Petrel in 2019. The wreck of the USS Yorktown is also located in the Monument. The remains of more than 3,000 military personnel are located inside and near the Monument's boundaries.