Plum Island Southold NY 11957: History, Wildlife, and Hidden Secrets

Plum Island is a federally owned, 840-acre island in Southold, NY 11957, located east of Orient Point in Gardiners Bay. It houses the Plum Island Animal Disease Center (PIADC), established in 1954. The island supports over 250 bird species and the largest seal haul-out in southern New England. Public access is restricted.

What Is Plum Island?

Plum Island sits in Gardiners Bay, east of Orient Point, off the eastern end of the North Fork coast of Long Island. It stretches about 3 miles long and 1 mile wide at its widest point, covering approximately 840 acres.

The island carries two identities. One is a working federal research facility. The other is an untouched natural habitat — forests, coastal dunes, marshes, and tidal wetlands that have stayed largely undisturbed for decades. Because scientists occupy only a fraction of the 840 acres, most of the land has remained wild since Fort Terry was decommissioned in the mid-20th century.

The name comes from the beach plums that grow along its shores. An old Dutch map from around 1640 labeled the island “Pruym Eyelant.” Before European contact, the Pequot people called it Manittuwond and used it seasonally for fishing and hunting.

A Brief History Worth Knowing

Plum Island’s recorded history begins in 1659 when Samuel Wyllys purchased it from Wyandanch, the senior chief of the four Long Island tribes. The purchase price was one coat, one barrel of biscuits, and 100 fishhooks. Land disputes followed for years, tangled in competing claims between Native leaders and colonial settlers.

The U.S. government took control in 1899, paying roughly $90,000 to build Fort Terry — a coastal defense installation designed to guard the entrance to Long Island Sound. During World War I and World War II, the fort served as a military post before being decommissioned.

In 1954, the United States Department of Agriculture established the Plum Island Animal Disease Center (PIADC). The center researches animal pathogens to protect farmers, ranchers, and the national food supply. In 2003, the Department of Homeland Security took ownership while the USDA continued its science mission on the island.

For years, rumors spread about biowarfare experiments and secret research. None of those claims has been substantiated. The restricted access exists because of the sensitivity of livestock disease research — particularly foot-and-mouth disease — not because of anything more sinister.

The Wildlife Case for Preservation

The research facility tells only part of Plum Island’s story. Ecologically, the island is significant on a regional scale.

Plum Island’s biodiversity includes more than 250 species of birds, with 60 or more that are endangered or threatened, and approximately 1,000 seals. The island boasts the largest seal haul-out in New York. Roseate terns, osprey, peregrine falcons, and piping plovers all use the island as habitat or migratory stopover. Rare plants cling to the northern cliffs — a glacial moraine that rises 100 feet above sea level.

Because the island has had almost no commercial development since the late 1800s, its ecosystems have remained intact in ways that are increasingly rare for the New York metro region.

When federal and state governments identified 33 stewardship sites around Long Island Sound, they called Plum Island and the surrounding Gull Islands an “exemplary” habitat area deserving of special protection.

The Fight to Preserve Plum Island

In 2008, Congress ordered the sale of the island to the highest bidder. The plan triggered a decade-long conservation battle.

A dozen years and much effort later, a provision in a 2020 bill took it off the auction block. Over 120 national, regional, and local organizations — coordinated through the Preserve Plum Island Coalition (PPIC) — pushed to block the sale. Congress acted, and President Trump signed the legislation in 2020.

The island’s future remains unresolved. As the Plum Island Animal Disease Center prepares to move its mission to a new laboratory in Kansas, the PPIC continues to advocate for comprehensive conservation and management solutions that would safeguard the island in the public trust. Conservation groups and the Town of Southold support designating it as a National Monument.

Pamela Hilburger and the Southold Connection

Plum Island falls under the Town of Southold’s jurisdiction — zip code 11957. The broader Southold area on Long Island’s North Fork has long attracted notable residents drawn to its quieter pace, coastal landscape, and proximity to New York City without the Hamptons price tag.

Pamela Hilburger is an American celebrity parent known for being the mother of supermodel Devon Aoki. She is a former jewelry designer and painter, and the ex-wife of Hiroaki “Rocky” Aoki, the late Japanese-American wrestler and founder of the Benihana restaurant chain. Hilburger is of German and English ancestry and has maintained ties to the New York area throughout her life.

Her connection to the Southold, NY 11957 address reflects a pattern common among New York-area personalities who have sought quieter, nature-adjacent communities on the North Fork—an area known for its farmland, vineyards, and direct access to Long Island Sound.

Can You Visit Plum Island?

You cannot visit Plum Island as a general tourist. The island is federally owned, and access is controlled by the Department of Homeland Security. There are no public ferry routes, no visitor facilities, and no overnight stays permitted.

The best views come from the water. The Cross Sound Ferry, which runs between Orient Point and New London, Connecticut, passes near enough to see the 1869 Plum Island Lighthouse on the island’s western end. East End Seaport also offers excursions that travel near the light.

If the island eventually transitions to a National Wildlife Refuge or Monument status, that would change. Conservation advocates have proposed guided tours and an educational facility on the island’s east side — though no timeline exists yet.

FAQs

What is the ZIP code for Plum Island, NY?

Plum Island falls under Southold, NY, ZIP code 11957. It is part of Suffolk County on Long Island’s North Fork.

Is Plum Island open to the public?

No. The island is federally owned, and access is restricted by the Department of Homeland Security due to ongoing animal disease research operations.

What animal research happens on Plum Island?

The Plum Island Animal Disease Center studies foreign animal pathogens, primarily to protect U.S. livestock from diseases like foot-and-mouth disease.

Who is Pamela Hilburger?

Pamela Hilburger is a jewelry designer and painter, best known as the ex-wife of Benihana founder Rocky Aoki and the mother of supermodel Devon Aoki. She has ties to the Southold, NY area.

What will happen to Plum Island in the future?

The PIADC is being relocated to a new facility in Manhattan, Kansas. Conservation groups are pushing to designate the island as a National Monument or National Wildlife Refuge.