Karen Lannon and her brother Hal Cushing have perhaps the most unusual piece of waterfront property in Greater Portland: a twenty-four-acre island complete with an artillery-ready, three-bastion granite fort. The two-story fort is fully equipped with walls, parapets, parade ground, and cavernous munitions bunkers and is suitable for repulsing any hostile parties who might wish to attack the Old Port with nineteenth-century naval assets. All Lannon and Cushing would need to hold back the steamers of the old Spanish Navy is a shipment of ten- and fifteen-inch Rodman guns, sixty trained artillerymen, and a large supply of ammunition.

Fortunately, Casco Bay isn’t under any immediate threat, so the siblings concentrate on the more mundane responsibilities of fort ownership. They mow acres and acres of lawns — every few days in springtime, the grass grows so quickly — and keep the walkways and outbuildings maintained for the tour parties they bring over from the city four times a week in season. Over near the old Immigration and Quarantine station there are lobster bakes to stage and weddings to cater, but at least they don’t have to clean up oil spills anymore. After their mother, the late Hilda Cushing Dudley, purchased the fort in 1954 to save it from being torn down, the family would regularly have to clean up their beach whenever oil spilled from tankers at the South Portland terminals. (“When we get a spill we get down on our hands and knees and clean it up,” she told a reporter in 1977. “People aren’t going to come out here if there’s oil all over the beach.”)

Asked what the hardest thing about fort ownership is nowadays, Hal doesn’t have to think. “Paying the taxes,” he says emphatically, referring to the $35,000 annual bill from Portland, of which House Island and Fort Scammell are a part. “We don’t have any services, but we’re charged by the square foot so we’re in the top ten tax residents in the city.”

But previous custodians of Fort Scammell and the network of other fortifications protecting Maine’s largest port had even worse things than taxes to contend with. They were slaughtered in Indian attacks in the seventeenth century, bombarded by British cannons in the eighteenth, suffered for lack of supplies, heat, and entertainment in the nineteenth, and shot at by suspected spies in the early twentieth. On the eve of World War II, thousands of soldiers and sailors manned anti-aircraft guns, heavy artillery, watch towers, and the controls for remotely-detonated mines, alert for a Nazi surprise attack that fortunately never came.

Visitors from the megalopolis to our south come to Portland to get away from it all, and to the islands, beaches, and headlands of Casco Bay for peace and quiet. The remains of forts and gun emplacements scattered about the area add to the mystique. But like the walled cities of France and Germany, Greater Portland’s extensive fortifications are reminders that for the first three centuries of its history, Maine’s largest city was a prime target for an enemy attack.

“Because of the wonderful harbor, it’s always been a potential target for any enemy so it was defended from the colonial period straight through World War II,” says Joel W. Eastman, an emeritus professor of history at the University of Southern Maine and the leading expert on Maine’s forts. “In World War II, it was agreed upon by the army and navy that Portland was tactically the most important harbor in the U.S. because of its proximity to Europe.”

The approaches to the city are still guarded by successive rings of now-obsolete fortifications. Granite forts like Fort Scammell, Fort Gorges, and Fort Preble (now home to Southern Maine Community College) protected the entrances to the harbor until the advent of modern, long-range naval artillery in the late 1860s. Massive rifled gun batteries at Fort Williams, Peaks Island, Cushing Island, and Two Lights kept Spanish and German dreadnoughts and cruisers far from Maine’s shores at the turn of the last century. Anti-aircraft guns, radar stations, and minefield stations kept submarines in check during World War II, a time when soldiers in southern Maine were ready to retreat into gas-proof bunkers in the face of chemical weapons attack.

“We have surviving examples of defenses from the War of 1812 through the 1940s, and a lot of them are open to the public,” says Eastman.

In the early days, Portland’s defenses weren’t up to snuff. The earliest, Fort Loyal, was built in 1678 in what was then the center of town, the foot of India Street, and served as town hall, jail, and refuge of last resort. It was pressed into the latter role in May 1690, when four hundred to five hundred French and Indian troops attacked the settlement. Grossly outnumbered, the settlers held out for four days before surrendering, at which point two hundred were murdered and left in a large heap a few paces from what is now the popular Benkay sushi restaurant. When a fresh Indian war broke out in 1716, authorities decided to demolish the fort and evacuate the city rather than risk another catastrophe.

Tragedy struck again in October 1775, when another stockade fort at the same location was unable to prevent the destruction of the town by a modest British force consisting of a small eight-gun converted merchantman and four diminutive support vessels. The bombardment, which lasted for nine hours, was augmented by the landing of British marines, who set fires in undamaged neighborhoods. By the time HMS Canceaux and her consorts left the harbor, the entire downtown and three out of four buildings in Portland had been destroyed. The lesson was not lost on military planners: Defending the city required that enemy ships not be allowed to enter the harbor. Gun batteries were placed on the South Portland shore and at elevated locations around the town, including Munjoy Hill, where Fort Allen and Fort Sumner parks are today. (Little remains of the earthwork forts, which in the late 1790s housed more than two hundred men.)

The new gun batteries were likely sufficient to keep British forces away from the anchorage, but keeping smugglers from going out was another matter. The years leading up to the War of 1812 were tense in Maine, where backcountry settlers were in the midst of a violent insurrection against the machinations of Massachusetts land barons. The struggle quickly spilled over into politics, as the land barons were generally members of the party of wealth and propriety, the Federalists, while the rebels were backed by the populist Jeffersonians. As war loomed, even fort building policies became hijacked by partisan agendas.

The Jeffersonians controlled the federal government and had imposed an embargo on trade with Britain; the Federalists dominated Massachusetts (of which Maine was still a part) and were deeply opposed. Portland’s Federalist merchant class snubbed Washington and carried on a lively and profitable smuggling trade with the British-controlled Maritimes. Unfortunately for them, the U.S. Secretary of War was a Maine Jeffersonian, Henry Dearborn, who came down on the smugglers with several thousand tons of bricks. He ordered the construction of two new forts straddling the main approach to the harbor — Scammell, at House Island, and Preble, at what’s now SMCC — and channeled their construction and supply to Jeffersonians, including his son, Henry Alexander Scammell Dearborn, a Portland attorney. Unabashedly partisan celebrations were held when the forts were completed in 1808.

“It was pork barrel politics, and the local populace saw them as ‘embargo forts’ designed to keep smugglers in rather than the British out,” says Joshua M. Smith, director of the American Merchant Marine Museum in Kings Point, New York, who has studied the forts’ creation. “Customs officials enforcing the embargo didn’t just get a salary, they got half of the proceeds of whatever they seized, so it could look like they were enriching themselves at the expense of their neighbors.” One official was tarred, feathered, and dumped naked on the deck of a ship tied up to the Portland docks. Fort Preble’s first commander called a naval warship into the harbor to help protect his men against a suspected attack by local merchants and sailors.

Scammell and Preble’s current appearance is mostly the result of late nineteenth-century improvements. In their original form, they looked much like Fort Edgecomb: a semi-circular battery of earth and brick protected from infantry or mob attack by a wooden blockhouse. “Forts in that era were built as a deterrent and all of them were whitewashed to make them really obvious,” notes Eastman. “They wanted to let navies know that the harbor was defended.” The message was apparently received. While the British occupied much of eastern Maine during the conflict, Portland was never attacked. In 1813, Fort Scammell fired warning shots at a British privateer (a mercenary-operated warship), which scattered off. It’s believed to be the closest Portland-based artillery ever came to open combat.

Life in the new forts was tedious and sometimes dangerous. Desertion rates were high and the muzzle-loaded cannon of the early nineteenth century had a way of going off prematurely. During training exercises in June 1826, one Fort Preble gunner was thrown over the wall by the force of such an explosion and landed on the beach seventy feet away without one of his arms. He died forty minutes later. Six years later, another Preble cannon went off while its gunner was ramming down its explosive cartridge; he survived, but had to have both arms amputated. Another enlisted man died after getting drunk, refusing to work, and being beaten with a stick and repeatedly dunked underwater by a junior officer. The rest of the men engaged in the back-breaking work of dismantling now-redundant Fort Sumner and using the materials to repair and improve Preble. (The old fort, a correspondent of Portland’s Eastern Argus declared, was a “monument of folly,” which was about as useful for defending the town “as it would have been on the summit of the White [Mountains].”

In the aftermath of the U.S. Civil War, Portland’s strategic importance had increased, but its defenses were no longer adequate. With the completion of the Grand Trunk Railroad to Montreal, the city had become the winter port for Quebec and Ontario, making it a target in any renewed conflict with Britain. “If Great Britain held the harbor of Portland,” Maine Governor Israel Washburn warned Congress, “she would drive American commerce from the ocean and the great lakes.” Unfortunately, modern artillery could not fire over Casco Bays outer islands, allowing ships to hammer the city’s forts from behind a protective screen. Defenses had to be upgraded, the governor warned, else “the first intimation of trouble with any leading foreign power would be the entrance of a hostile fleet into Portland Harbor.”

The result was a major upgrade of the existing forts and the construction of an outer ring of defenses: Fort Lyon on Cow Island (1896), Fort Williams next to Portland Head Light on Cape Elizabeth (1898), Fort Levett on Cushing Island (1900), and Fort McKinley on Great Diamond Island (1901). Rushed into service during the Spanish-American War, the system featured disappearing rifled artillery pieces, power, and steam plants.

How effective was it? To find out, the U.S. Navy staged a massive war game in Casco Bay in August 1903. Three 12,000-ton battleships — including the flagship of the North Atlantic Fleet, USS Kearsarge — attempted to run the main passage at night, exchanging mock fire with Williams, Preble, Levett, and Scammell. Meanwhile, two fast destroyers and a variety of small craft threatened the secondary passages near Diamond and Cow islands. The result: all three battleships technically destroyed after being spotted with searchlights and the initial landings on minor islands repulsed. But after receiving reinforcements, the attacking fleet anchored off Crescent Beach, sent marines to storm Cape Elizabeth, and ultimately captured Fort Williams overland. Portland, the exercises suggested, was still vulnerable to an amphibious assault.

The defenses were covertly tested during World War I, this time by a shadowy enemy that was never identified. In March 1917, prowlers repeatedly infiltrated restricted areas around the new twelve-inch gun batteries at Fort Williams. Cordons of sentries were deployed to protect the guns and man searchlights, but on March 23 two infiltrators got in anyway and exchanged fire with a sentry, killing twenty-two-year old Private John Poor with a .44 caliber bullet. The strangers escaped, possibly to one of the German submarines rumored to have been lurking off the coast.

But it was in the lead-up to the U.S. joining World War II that Portland’s defenses were on highest alert. “We were initially worried about Germany winning in Europe and attacking the United States,” Eastman notes. “Portland had an explosion in activity.”

Coastal artillery units were called up in 1940 and draftees were sent to Fort McKinley for basic training. Anti-aircraft guns, radar stations, and search towers were deployed all over the area, and heavy guns were erected at Two Lights and at Peaks and Jewell islands. Fort Gorges was turned into a mine storehouse, gun batteries were retrofitted against poison gas attacks, and minefields were deployed throughout the bay.

The attack never came, and by the time the war ended, aerial assaults, rockets, and atomic weapons had made coastal artillery obsolete. Between 1948 and 1950, the military closed most of its Casco Bay instillations. In 1960, Fort Williams, a recruiting station, was the last to go. The surplus properties were offered first to other federal agencies, then state ones, municipalities, and private interests in that order. The state took Two Lights (now a park), Jewell Island (a popular recreation area), and Fort Preble (SMCC); Cape Elizabeth bought Fort Williams (also a park), Portland took Fort Gorges, and Fort McKinley, the Long Island fuel base; and, of course, Fort Scammell wound up in private hands.

“They were going to tear it up and use it for the Spring Point breakwater,” says House Island owner Karen Lannon, shaking her head as she walks a tour party back toward the boat. Hal, in the wheelhouse, sounds the horn, which echoes to nearby Peaks. “This piece of history would have been lost.”