Long Island extends 118 miles from New York City into the Atlantic Ocean — and its abandoned landscape is as layered as its geography. A psychiatric campus with 150+ buildings closed in 1996. A Cold War radar installation at the island's eastern tip linked to conspiracy theories about government mind control experiments. Gilded Age estates returning to the forest. WWII coastal defense batteries on the Atlantic shore. Here are 5 of the best abandoned places in Long Island, selected from our Abandoned Places Map USA — 5,000+ GPS locations across the United States.
Why Long Island Is a Hidden Gem for Abandoned Buildings & Urban Exploration
Long Island's urbex landscape spans from the western end's industrial decay to the Hamptons' forgotten estates and the East End's Cold War military infrastructure. The island's proximity to New York City means development pressure is intense — but its size means enough has survived to make it one of the richest single-county urbex regions in the northeastern United States.
1. Kings Park Psychiatric Center – 1885 Victorian Asylum with 150+ Buildings, 9,000 Patients at Peak, Closed 1996, Nissequogue River State Park (Known Location)
Established in 1885 as the Kings County Farm — a farm colony to house and rehabilitate Brooklyn's psychiatric patients — Kings Park grew over a century into a massive campus of 150+ buildings housing 9,000 patients at its 1950s peak, complete with its own farms, power plant, railroad and cemetery. Building 93, a 13-story Art Deco tower built in 1939, still dominates the campus skyline. When deinstitutionalization emptied the wards and the last patients were transferred in 1996, the buildings were locked and left. The surrounding land became Nissequogue River State Park, making the exteriors accessible. Inside the buildings, original fixtures, patient records and personal belongings remained as they were left. One of the most significant and most visited abandoned places in Long Island — essential urbex for anyone exploring New York.
🔗 Learn more: Wikipedia – Kings Park Psychiatric Center
2. Camp Hero State Park – 1942 WWII Radar Station Linked to the "Montauk Project" Conspiracy, Bunkers and Radar Tower Still Standing, Montauk (Known Location)
Built in 1942 as a coastal artillery and radar installation at the eastern tip of Long Island, Camp Hero protected New York City's approach from German naval and air attack. The base was decommissioned in 1981 when the AN/FPS-35 radar tower — still standing at full height in the park — became obsolete. Camp Hero became a state park in 2002, but persistent conspiracy theories claim that secret government experiments in mind control, time travel and teleportation — "The Montauk Project" — were conducted underground after the official closure. No evidence supports the claims; the concrete bunkers, abandoned military buildings and the massive radar tower are real and freely explorable. One of the most atmospheric and most distinctive abandoned places in Long Island.
🔗 Also read: Top 5 Best Abandoned Places in the USA →
3. Pilgrim State Psychiatric Center – 1931 Asylum That Was the World's Largest Hospital, 14,000 Patients at Peak, West Brentwood (Exclusively on Our Map)
Built in 1931 in West Brentwood, Pilgrim State Psychiatric Center was at its 1950s peak the largest hospital in the world by patient count — 14,000 patients on a 900-acre campus with its own railroad station, farm, power plant and police force. As deinstitutionalization reduced the population, building after building was closed and sealed. Many of the original 1930s structures still stand in various states of abandonment alongside the portions of the campus still in operation. One of the best abandoned places in Long Island for institutional scale — a hospital so large it was a city unto itself. Exact location available on our Abandoned Places Map USA.
4. Abandoned Gilded Age Estate – 1890s North Shore Mansion with Carriage House and Formal Gardens, Nassau County (Exclusively on Our Map)
Long Island's Gold Coast — the North Shore from Great Neck to Lloyd Neck — was once the most concentrated collection of Gilded Age estates in America, inspiration for F. Scott Fitzgerald's The Great Gatsby. Dozens of these mansions have been demolished; the survivors exist in various states of preservation and abandonment. This estate retains its carriage house with original harness rooms, the formal garden's stone balustrades and fountains and the main house visible behind locked gates, the grounds reverting to secondary woodland after decades of neglect. One of the most evocative abandoned places in Long Island for Gatsby-era architectural decay. Exact location available on our Abandoned Places Map USA.
5. Fire Island WWII Coastal Artillery Battery – 1942 Concrete Gun Emplacements with Ocean Views, Fire Island National Seashore (Exclusively on Our Map)
A WWII coastal artillery installation on Fire Island — built in 1942 to defend New York Harbor from German naval attack, the concrete gun emplacements and fire control bunkers sit within the Fire Island National Seashore, their walls decorated with decades of graffiti and the Atlantic Ocean visible through the gun port openings. Accessible by ferry from Bay Shore, the installation is one of the best abandoned places in Long Island for coastal military urbex — ocean-facing concrete infrastructure from the most significant conflict in American history. Exact location available on our Abandoned Places Map USA.
Safety Tips for Urban Exploration in Long Island
- New York enforcement: Long Island has strict trespassing enforcement — always verify legal access and never enter sealed buildings on active institutional campuses like Kings Park or Pilgrim State
- Coastal sites: Fire Island and Camp Hero coastal installations have unstable concrete and slippery surfaces — wear non-slip footwear and never approach cliff or dune edges
- Never explore alone — always bring at least one other person and let someone know your location
The urbex code applies everywhere: "Take nothing but photographs, leave nothing but footprints."
❓ FAQ – Abandoned Places in Long Island
What is the most famous abandoned place in Long Island?
Kings Park Psychiatric Center in Nissequogue — a Victorian asylum established in 1885 that grew to house 9,000 patients, with 150+ buildings including the 13-story Art Deco Building 93. Closed in 1996 and now surrounded by state park land, it is one of the most visited abandoned institutional sites in the northeastern United States.
What is the Montauk Project at Camp Hero?
Camp Hero in Montauk was a real WWII and Cold War radar installation that operated until 1981. The "Montauk Project" is a conspiracy theory claiming secret government experiments in mind control and teleportation were conducted underground after official closure. No evidence supports the claims, but the concrete bunkers, military buildings and massive radar tower are real and freely accessible in the state park.
What was Pilgrim State Psychiatric Center?
Built in 1931 in West Brentwood, Pilgrim State was at its 1950s peak the largest hospital in the world by patient count — 14,000 patients on a 900-acre campus with its own railroad station, farm and power plant. Many of the original 1930s buildings still stand in abandonment alongside the portions of the campus that remain active.
🎯 Summary
Long Island's abandoned buildings span from the world's once-largest hospital to a Cold War radar tower linked to government conspiracy theories and Gilded Age estates returning to the North Shore forest. Each of these 5 abandoned places in Long Island captures a different layer of an island shaped by immigration, industry, Cold War military ambition and the extraordinary wealth that built its Gold Coast and eventually walked away.
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