Casco Bay Islands — Long Island, Chebeague, Great Diamond, Little Diamond, and Cliff Island -- Five Distinct Places, One Ferry System

Five Islands, One Ferry System, Five Different Identities

Start with the scope: this page is about the other Casco Bay islands, not Peaks Island. Peaks is the largest, most populous, and most frequently ferry-served of the group -- a genuine Portland neighborhood with its own commuter-ferry identity, its own pending secession bill (LD 1079/HP0814), and its own WWII gun battery, Battery Steele. All of that is already covered in depth on this site's own dedicated Peaks Island page. What follows here is Long Island, Chebeague Island, Great Diamond Island, Little Diamond Island, and Cliff Island -- five communities that share a ferry carrier and a stretch of water, but very little else.

Long Island is the closest analogue to Peaks Island's secession story, but it's a genuinely separate and earlier one. Long Island seceded from the City of Portland on July 1, 1993, after Portland's 1990 property-tax revaluation sharply raised taxes on the island relative to the municipal services residents actually received. It's a small place -- 234 year-round residents at the 2020 Census, swelling to roughly 800 to 1,000 in summer, on just 1.42 square miles of actual land (the town's total area of 33.52 square miles is almost entirely water). Its history includes WWI- and WWII-era military installations, a destructive June 1914 fire, a failed 1969 supertanker-port proposal, and a real, documented 1972 oil spill from the tanker Tamano that contaminated West Beach. Long Island relied on farming, fishing, and lobstering before tourism became its dominant industry after World War II. Casco Bay Lines ferry trips run roughly 30 minutes to an hour.

Chebeague Island is the largest of these five and the fullest-served. It seceded from the town of Cumberland on July 1, 2007, after 184 years, via a real Maine Legislature public law (PS Law Chapter 47) following an April 5, 2006 statewide vote (Senate 31-3, House 131-1) -- the driving motivation was protecting Chebeague's own small elementary school from Cumberland-district downsizing pressure, a different trigger entirely from Long Island's tax dispute. Chebeague had 396 year-round residents at the 2020 Census, up 16% from 2010, with a summer population more than triple that; its land area is 3.56 square miles (24.56 total, mostly water). It's also the only island in this group served by two separate ferry operators: the Chebeague Transportation Company runs a roughly 15-minute passenger run from Cousins Island in Yarmouth to the island's Stone Wharf, plus a vehicle and freight barge from April through November, while Casco Bay Lines runs a longer, roughly 60- to 90-minute mail-boat route from downtown Portland to Chandler's Cove wharf. Chebeague also has its own Great Chebeague Golf Club, a nine-hole course whose clubhouse -- a repurposed circa-1807 residence -- was listed on the National Register of Historic Places in 2015.

Great Diamond Island has never been its own town; it's always been part of Portland, with no secession story. Its year-round population was 77 at the 2000 Census -- the most recent figure independently confirmed -- though a commercial demographics aggregator shows a much smaller current snapshot of 12 residents; that discrepancy is flagged here rather than resolved. Casco Bay Lines serves a Diamond Cove stop on the island's northeastern side. The island's real identity is Fort McKinley: originally called Great Hog Island and home to a 19th-century artistic retreat (Henry Wadsworth Longfellow and Harriet Beecher Stowe are both associated with it), it became a major coastal-defense installation built roughly 1897 to 1906, eventually covering 111 acres with nine gun batteries -- described as Casco Bay's largest military installation. The fort closed in 1947 and was sold to private interests in 1961; the Fort McKinley Historic District was listed on the National Register of Historic Places in 1985. Today Diamond Cove is a gated, mostly private residential community built from the old barracks and officers' quarters, with Diamond's Edge Restaurant & Marina and the Diamond Cove General Store as its public-facing businesses. This is a different fort and a different history than Peaks Island's Battery Steele, which belongs to that island's own page.

Little Diamond Island is, honestly, barely inhabited. It had just 5 year-round residents at the 2000 Census, a figure explicitly tied to the fact that the island's water supply is shut off in winter, limiting who can live there permanently -- a more recent commercial demographics source shows an even smaller current snapshot of 2 residents. It's part of Portland, formerly called Little Hog Island, and is predominantly privately owned. Little Diamond functions as a vacation retreat, not a residential community, and no dining establishment of any kind was found there this research pass -- its identity really is its thinness, and that's stated here honestly rather than dressed up.

Cliff Island is the farthest and most rustic of the group. Its year-round population is roughly 60 (2000 Census), swelling to about 200 in summer, on Portland-owned land with no secession story. It's the longest Casco Bay Lines run of the five -- commonly cited at 60 to 120 minutes one way -- with five daily round trips year-round and its own ZIP code, 04019. Cliff Island is the only year-round-inhabited island in Casco Bay with entirely unpaved roads; residents get around by walking, bicycle, and golf cart rather than car. Current island employment includes lobstering alongside local businesses and mainland commuting. Its one dining option is the Cliff Island Store & Cafe.

Two current, dated civic stories cut across all five islands (and Peaks Island too, since they all ride the same ferry system). First, the 2026 Casco Bay Lines fare fight and the resulting Maine PUC investigation, detailed above. Second, a July 2025 Portland Press Herald investigation into housing shortages across Maine's 15 unbridged islands -- explicitly naming Chebeague, Long Island, Peaks, and Cliff Island -- found a median island resident age of 56 versus 44 statewide, construction costs roughly 30% higher than the mainland due to barge transport, and land supply constrained by conservation easements. On Chebeague specifically, the Chebeague Island Community Association has run real, named affordable-housing projects for over a decade, including two modular duplexes (installed May 2012 and May 2025) built with MaineHousing grants.

On fishing and boating, Chebeague has the clearest documented lobstering identity: Calendar Islands Lobster, a fishermen-owned cooperative launched in 2009 by Dropping Springs LLC with Island Institute support, grew to 29 participating fishermen -- its current operating status wasn't independently confirmed this pass, so it's stated here as a real historical founding effort, not a confirmed active business today. A separate, more recently active business, Chebeague Island Lobster Co., is real and findable via business listings, though its current status is likewise unconfirmed. Dining rosters across all five islands are genuinely thin -- Chebeague has the fullest, with the Chebeague Island Inn, The Niblic at the Boat Yard, and the Slow Bell Cafe; Long Island has Byers & Sons Long Island Bakehouse and the Long Island Store; Great Diamond has Diamond's Edge Restaurant & Marina and the Diamond Cove General Store; Cliff Island has the Cliff Island Store & Cafe; Little Diamond has none found. Small seasonal island businesses can close or change hands quickly, so any name here should be spot-checked before relying on it.