You’re driving through the quiet, salt-sprayed neighborhood of Squantum in Quincy, looking at the skyline of Boston across the water, and you see it. A long, thin causeway stretching out into the bay, leading to a green, mysterious mound of land. That’s Moon Island Quincy MA. It looks like the perfect spot for a weekend hike or a sunset photo.
But then you hit the gate.
There’s a guardhouse. There are signs. Very clear, "do not enter" signs. Honestly, it's one of the most frustrating spots in the Boston Harbor Islands National Recreation Area because it’s right there, physically connected to the mainland, yet completely off-limits to the average person.
The Mystery of Moon Island Quincy MA
So, why is it closed? It’s not a secret government bunker or a private billionaire’s retreat. The 44-acre island is actually owned by the City of Boston, even though it sits within the jurisdiction of Quincy. This weird jurisdictional quirk—Boston land in a Quincy zip code—has caused legal headaches for decades.
🔗 Read more: Finding Another Name for Tour Guide: What the Pros Actually Use
Today, Moon Island serves two very loud, very official purposes. It houses the Boston Fire Department Training Academy (recently renamed the Capt. Leo T. Sullivan Training Academy) and the Boston Police Department’s shooting range. If you live in Squantum, you don't need a map to find Moon Island; you just need to listen for the occasional pop-pop-pop of practice rounds or see the plumes of controlled-burn smoke during fire drills.
What’s Actually on the Island?
If you managed to get past the guardhouse at the end of Dorchester Street, you’d find a landscape that feels like a strange mix of a movie set and an industrial relic.
The Fire Academy
The north end is dominated by the fire academy. They have a massive concrete building designed specifically to be set on fire over and over again. It’s built with different roof pitches and window styles to simulate the various types of architecture firefighters encounter in Boston’s neighborhoods—think triple-deckers and brownstones. There’s even a "fire engine graveyard" out there with old rigs used for training.
The Police Range
On the southern side, there’s the shooting range. This isn't just for target practice for current officers. If you’re a resident of Boston or Brookline and you want a License to Carry (LTC), you basically have to go to Moon Island to prove you can shoot.
The qualification is pretty specific:
- You fire 30 rounds with a .38 special revolver.
- You shoot at 7 yards and 15 yards.
- You need a score of 210 out of 300 to pass.
It’s an outdoor range, so if you’re taking your test in January, you’re dealing with the brutal wind coming off Quincy Bay.
The Bridge to Nowhere (and the Long Island Drama)
You can't talk about Moon Island Quincy MA without mentioning the bridge—or the lack of one.
🔗 Read more: Suitcase locks with keys: Why I still use them in a digital world
For years, Moon Island was the gateway to Long Island, which housed a homeless shelter and a recovery campus. In 2014, the bridge connecting Moon Island to Long Island was abruptly closed because it was structurally sound as a piece of Swiss cheese. It was demolished shortly after.
Since then, Moon Island has been the frontline of a massive political war. Boston wants to rebuild the bridge to reopen the recovery facilities. Quincy? Not so much. Quincy officials and Squantum residents are worried about the traffic of hundreds of construction vehicles and eventually buses rolling through their quiet streets to get to Moon Island. As of early 2026, the legal battles are still simmering in the courts, with Quincy recently filing new suits to block the construction, citing environmental concerns about the old piers and rising sea levels.
A History of Sewage and Stone
Long before it was a training ground, Moon Island was a farm. In the 1600s, it was called "Munning’s Moone." Local Indigenous tribes had used the area for thousands of years before that; archaeologists actually found stone blades on the nearby beaches in the 60s.
The biggest change came in the late 1800s. Boston had a massive problem: sewage was everywhere. To fix it, they built a giant system that funneled waste to Moon Island. They carved out the hill to build four massive granite reservoirs. They’d hold the "material" there and wait for the tide to go out. When the tide was ebbing, they’d open the gates and flush it all into the outer harbor.
It was a marvel of engineering for 1884, costing about $6 million (which is nearly $200 million today). Those granite tanks are still there, though the system was shut down in the late 1960s.
Can You Ever Get There?
Short answer: No.
✨ Don't miss: Weather in Twin Falls ID: What Most People Get Wrong
Long answer: Unless you are a first responder, a student at the fire academy, or a civilian taking a firearms qualification test, you aren't getting on that causeway. The Boston Public Health Commission Police guard the entrance 24/7.
Even the water access is tricky. While the lagoon between Moon Island, Thompson Island, and Squantum is a popular spot for boaters to anchor because it's protected from the wind, you can't just hop out and wander onto the beach. It’s restricted.
Actionable Takeaways for Locals and Visitors
Since you can't actually hike Moon Island, here is how you can still experience the area:
- Best View: Head to Squaw Rock (Chapel Rocks) in Squantum. It’s a short hike with incredible views of Moon Island and the Boston skyline. You can see the old granite sewage tanks from the cliffs.
- Boating: If you have a kayak or a boat, the "Moon Island Lagoon" is one of the calmest spots in the harbor for an afternoon at anchor. Just stay below the high-tide line if you get close to the shore.
- Firearm Licensing: If you’re a Boston resident applying for an LTC, don't just show up. You have to book your qualification through the Boston Police Department, and they’ll give you the clearance to pass the guardhouse.
- Stay Updated: Follow the local Quincy and Boston news regarding the "Long Island Bridge" replacement. The outcome of that legal battle will determine if Moon Island stays a quiet training ground or becomes a busy transit corridor again.
The island remains a strange, quiet sentinel in the harbor. It’s a place of history, high-stakes politics, and a whole lot of "Keep Out" signs. While it’s tempting to try and explore the old ruins, it's best to enjoy this one from the safety of the Squantum shoreline.