1 Big Sustainable Island

Island Treehouse on Lake: Pet-Friendly Glamping

Unique treehouse glamping experience on Annabessacook Lake in Monmouth, Maine — near Winthrop.

Quick Answer: Island Treehouse on Lake: Pet-Friendly Glamping is The Oaktagon Tree House is what happens when you decide to live with the forest instead of just visiting it. Built around a living red oak (her name is Annie), this octagonal tree house invites you up into the canopy, where birds provide the soundtrack and the lake glimmers below. Perched on a 14-acre island just a half-mile from shore, it’s a place to slow down, look outward through leaves and branches, and remember what it feels like to be held by trees on Annabessacook Lake in Monmouth, Maine.

The Oaktagon Tree House is what happens when you decide to live with the forest instead of just visiting it. Built around a living red oak (her name is Annie), this octagonal tree house invites you up into the canopy, where birds provide the soundtrack and the lake glimmers below. Perched on a 14-acre island just a half-mile from shore, it’s a place to slow down, look outward through leaves and branches, and remember what it feels like to be held by trees.

Guest Reviews from Revyoos — Showing 10 of 153 Reviews

Justin September 27 2026
Oaktagon Weekend Getaway.
Rating: 5.0 / 5

The island is the perfect blend of remote and accessible. The limited number of free ferries actually makes it easier to disconnect from mainland life (aka the grind) and just be present on the island (safe in the knowledge that in the event of an emergency, staff would spring into action to get the boats running). The oaktagon tree house was majestic, smelled amazing (100% cedar paneling) and was a short walk from the water where we watched a majestic sunrise. The toilets are clean, accessible, and super eco friendly, the "showa" warm (be prepared for an upper body workout to pressurize the water, but its super worth it after a long day of paddling around). Unlimited firewood and well cared for woodstoves make for a warm cozy night. Both staff and fellow campers were extremely accommodating, polite and friendly.<br/><br/>If you come in acorn season, be prepared to be pelted. All night. All day. Its like a firing range of hailstones.<br/>

Barb September 26 2026
Rating: 5.0 / 5

Unique setting with thoughtful details<br/><br/>

Barry September 24 2026
It was definitely a fun and exciting experience.
Rating: 5.0 / 5

We loved the location, I really enjoyed sitting on the docks at night. Looking at the stars, listening to the loons. Just enjoying a nice peaceful evening over the lake...wishing the hammock dock was more assesibile without getting wet! I wished I could do some fishing. I would love to experience the locations as well. Overall, It was a great experience and my husband and I would love to do it again! We will come back in the summer of 2027! You guys do a great job with maintaining the property and taking care of your customers. Thank-you<br/><br/>Nothing, everything was good.<br/>

Wade September 12 2026
Rating: 5.0 / 5

1 Big Sustainable Island is a great place to visit! Kent picked us up at the dock and dropped us off at the front of our accomidation, and from there left us to explore and enjoy all the nature and trails the island had to offer. We only spent one day at the Oaktagon so we didnt get to take advantage of all the activities the island had to offer but it would have been easy seeing ourselves spend more time there. We definitly should have brought more food and taken advantage of the firepit and propane grill. Congrat's on the new baby!

Steven September 11 2026
Rating: 5.0 / 5

Paddling out to an island to spend a couple nights in a tree house felt like a mini adventure. However, Kent has everything in place to make it safe and comfortable without alot of logistics to figure out.<br/>I was looking for a peaceful place to decompress and I found it. I chose to just relax... reading in the hammock, walking the trails, and fishing off the dock (a mess of bass and even a pike). But, there are other things to do for those who want to be more active.<br/>Highly recommend

Marina September 01 2026
Rating: 5.0 / 5

10/10 — We Already Can’t Wait to Come Back!<br/>The Oaktagon Tree House completely exceeded our expectations. We originally booked our stay for our anniversary, and we loved it SO much that we literally weren’t ready to leave — so we booked an extra night in the Dome unit!<br/>Everything was incredibly clean, comfortable, peaceful, and so thoughtfully put together. They truly thought of everything. We had all the supplies and amenities we could possibly need, plus so many little extras that made the stay feel special.<br/>The private dock and paddle boarding were such a highlight. Being able to just slow down, enjoy the water, take in the quiet, and completely disconnect from everyday life was exactly what we needed.<br/>And the staff? AMAZING. So welcoming, helpful, and genuinely kind. You can tell how much care goes into making sure guests have an incredible experience.

Analiese August 11 2026
Rating: 5.0 / 5

My family of 5 had a great time at the Oaktagon! It had everything we needed, so we didn’t have to worry about lugging tons of things to the island. It was a beautiful, quiet location. We’re already talking about going back!

Lindsay June 20 2026
Rating: 5.0 / 5

Kent was super nice. He’s put so much thought into the island. There’s a ton of work that goes into a place like this, and he truly has thought of so many amazing details. A really special place! There are several really unique lodging options on the island, so take a look at the various options before making your choice. One thing to note is that this one is right next to the small “events tent”. While there wasn’t an event going on and things were incredibly private for us, this may not always be the case, so I’d inquire before booking if you’re looking for a super private getaway. The different lodging options are far enough away from one another where you don't really notice other guests. A great "camping" experience for those who like a few extra comforts!

Annie June 13 2026
Rating: 5.0 / 5

Our stay on 1BSI was nothing short of amazing! The island is such a unique and well-curated space. There are plenty of supplies, such as water, battery packs, lighters, and anything else you might need. We stayed in the Oaktagon, which had all the amenities of an indoor space with the beauty of the gorgeous oak tree. We hope to be back soon!

diane B. July 01 2026
Rating: 4.0 / 5

Enjoyed our time in the oaktagon on the island. Staff is extremely friendly and responsive to any needs. Island is quiet and everyone we met was friendly. When I needed some pots and pans, they delivered them right off. The owner keeps in touch and there is a help button to use if you need something that is not there. My only comment would be to have someone pay a bit more attention to the bbq grill and cob webs inside the camp.

Oaktagon Treehouse FAQs

What's special about this treehouse stay?

Sleeping in the canopy offers a new perspective - birds at eye level, lake breezes through the trees, and a quiet sense of being tucked into the forest.

Is this stay suitable for kids or pets?

Who doesn't love a tree house! Kids and pets are welcome, and there's lots of space for them.

What's included in the stay?

Comfortable sleeping arrangements, private bathroom, firewood, cooking essentials, canoe/kayak access, and full use of island trails, a hammock swim dock, boat dock, swimming spots, and shared beach and shower.

How do I access this stay?

Arrive at the island by paddle, ferry, or boat, then follow marked trails to your Oaktagon Treehouse.