📌 Deciding when to visit? Read our honest Best Time to Visit Bar Harbor guide — a season-by-season breakdown of crowds, weather, and costs.
Mount Desert Island is the crown jewel of the Maine coast — a 108-square-mile island that is home to Acadia National Park, the towns of Bar Harbor, Northeast Harbor, Southwest Harbor, and Bass Harbor. Connected to the mainland by a short bridge on Route 3, MDI offers some of the most dramatic coastal scenery in the eastern United States with granite peaks, fjord-like sounds, and crystal-clear lakes all within a compact and endlessly explorable island.
Mount Desert Island is not the same thing as Acadia National Park. Acadia covers much of the island, and the island also holds Bar Harbor, Northeast Harbor, Southwest Harbor and Bass Harbor. See our Acadia vs Mount Desert Island explainer. Before you go:
- Park pass: Acadia requires an entrance pass, including for Island Explorer riders heading into the park. Check nps.gov/acad for the current fee.
- Free bus: the Island Explorer is fare-free and serves villages, trailheads and Schoodic, but it does not go to the Cadillac Mountain summit.
- Cadillac summit road: a vehicle reservation is needed in season. Our scenic drives guide has the details.
- Nova Scotia ferry: The CAT crosses to Yarmouth in about 3.5 hours. It ran May 14 to October 14 in 2026.
Getting Around Mount Desert Island
The Island Explorer bus system connects all major villages and Acadia trailheads daily through mid-October (in 2026, through October 13, with reduced fall service starting August 18) — free, reliable, and highly recommended for avoiding summer parking headaches. The 27-mile Park Loop Road is the classic MDI driving tour hitting Thunder Hole, Sand Beach, Otter Cliffs, and the summit of Cadillac Mountain. The 45 miles of historic carriage roads built by John D. Rockefeller Jr. are open to hikers, cyclists, and equestrians and are among the finest car-free recreational paths in America.
Beyond Bar Harbor
Northeast Harbor is a refined yachting village with excellent galleries, a charming main street, and the stunning Thuya and Asticou Azalea Gardens. Southwest Harbor is quieter and more local in character with the Wendell Gilley Museum of Bird Carving and the famous Hinckley boatyard. Bass Harbor Head Lighthouse on the island’s southern tip is one of the most dramatically situated lighthouses in Maine and one of the most photographed in New England.
Things to Do on Mount Desert Island
Hiking in Acadia offers over 150 miles of trails ranging from easy shoreline walks to demanding ridge scrambles on the Precipice and Beehive trails with iron rung ladders up near-vertical granite faces. Sea kayaking around the island’s rocky shores is world-class with guided tours departing from multiple locations. The Abbe Museum in Bar Harbor tells the story of the Wabanaki people with outstanding collections and thoughtful programming. Whale watching cruises depart from Bar Harbor throughout the summer with reliable sightings of humpbacks, finbacks, and minkes. Read our complete Acadia National Park Visitor Guide — hikes, drives, Cadillac Mountain, carriage roads, camping, and practical tips.
Day Trips from Mount Desert Island
The Schoodic Peninsula — the only mainland section of Acadia National Park — is roughly an hour east by road, and the Island Explorer serves it in season. Deer Isle and Stonington are about 90 minutes west along the Blue Hill Peninsula for a scenic contrast to MDI’s busier summer scene. The CAT ferry runs from Bar Harbor to Yarmouth, Nova Scotia, a crossing of about 3.5 hours, so it suits an overnight better than a day trip. In 2026 it ran from May 14 to October 14; check Bay Ferries for next season’s dates and bring a passport.
Looking for work on Mount Desert Island? Browse Jobs on MDI on JobsInMaine.com.
Wondering how Mount Desert Island relates to Acadia National Park? See our Acadia vs Mount Desert Island explainer.
Mount Desert Island FAQ
Is Mount Desert Island part of Acadia National Park?
Partly. Acadia National Park covers a large part of Mount Desert Island, but the island also has towns, villages and private land, including Bar Harbor and Southwest Harbor. The park also includes the Schoodic Peninsula on the mainland and Isle au Haut. See our Acadia vs Mount Desert Island explainer.
Do I need a car on Mount Desert Island?
Not always. The free Island Explorer bus connects the island’s villages, many trailheads and carriage road entrances, and Hancock County-Bar Harbor Airport in season. It does not go to the Cadillac Mountain summit, and a car is handy outside the bus season.
How do I get to Mount Desert Island?
By road, over a short bridge from the mainland on Route 3 through Trenton, about an hour past Ellsworth. You can also fly into Hancock County-Bar Harbor Airport, which the Island Explorer serves in season, or take The CAT ferry from Yarmouth, Nova Scotia.
Want a look at the island before you go? Our Bar Harbor webcams page lists live cams of Bar Harbor, Frenchman Bay, Jordan Pond and other Mount Desert Island harbors.
Our details come from the National Park Service and Bay Ferries, checked in October 2026.
Keep Reading
- Acadia National Park guide: Hikes, drives and practical tips
- Acadia vs Mount Desert Island: What is the difference
- When to visit Bar Harbor: Crowds, weather and costs
- Best scenic drives in Maine: Park Loop Road and more
- Deer Isle: A quieter island to the west
- First Sunrise in the US