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  • Writer's pictureTim Murphy

Fort Mifflin: The Fort that Saved America

Tucked away from the sprawl of Philadelphia International Airport stands one of the most significant forts in American history. Fort Mifflin was a Patriot stronghold that defended the Delaware River during the early years of the Revolutionary War. American soldiers put up a valiant defense here in late 1777 when British forces attempted to gain control of the Delaware after having captured Philadelphia. For six bloody weeks, British forces shelled the fort with a relentless torrent of artillery fire, but the Americans refused to surrender. The Patriots ultimately withdrew from the fort in mid-November; however, they successfully prevented the British from engaging General George Washington's troops in battle before the winter months. Without Fort Mifflin's fierce resistance, it is plausible to assume that the British Army would have forced the weakened and demoralized Continentals to surrender, effectively ending the American Revolution and the prospect of a sovereign nation.

Southeast Walls of Fort Mifflin

Fort Mifflin was first commissioned as Mud Island Fort in 1771 by the Pennsylvania Provincial Assembly to protect the Delaware River and the ports of Philadelphia. General Thomas Gage, commander-in-chief of British forces in North America, appointed Captain John Montresor of the British Corps of Engineers to design the fort’s defenses. Montresor developed an elaborate plan that would retain "32 pieces of cannon, 4 mortars and 4 royal howitzers...which at 6 men each make 240 men required, 160 musketry, in all 400 garrison" at an estimated cost of £40,000. However, the provincial government only allocated £15,000, forcing Montresor to drastically redesign his plans.

Frustrated by the lack of funds, Montresor abandoned the construction site in July 1772. Only the southeast walls were completed at the time of his departure. The fort sat unfinished for several years until the Continental Army acquired and completed the project in 1776.

In September 1777, following the Continental Army’s humiliating defeat at Brandywine, General William Howe and his triumphant Redcoats captured Philadelphia. While the Patriot capital had fallen into enemy hands, Continental strongholds still surrounded the city, preventing British supply ships from reaching port. General Howe realized that if his army could not resupply while in Philadelphia, they would be unable to engage General George Washington and the Continental Army in battle before breaking for winter quarters. Time was of the essence. He ordered his troops to sail up the Delaware River and engage and eradicate any pockets of Patriot resistance they encountered.

The Mud Island Fort was located in a strategic area across from Fort Mercer, New Jersey, where the Schuylkill River emptied into the Delaware. Before the Revolution, the fort held a garrison of two hundred men commanded by Colonel Samuel Smith. By the autumn of 1777, four hundred men were stationed at Mud Island while a small flotilla under the command of Commodore John Hazelwood patrolled the river. The defenders were tasked with holding off the British “to the last extremity” so that Washington could safely march his army to their winter encampments at Valley Forge.

The Siege of Fort Mifflin (September 26 – November 6, 1777)

“The garrison, with scarce anything to cover them but their bravery, survived in the midst of the mud,

shot & shells, and were obliged to give up more to the powers of time & gunpowder than to military superiority.”

– Thomas Paine, on the defense of Fort Mifflin

The British Navy laid siege to Mud Island on September 26, 1777. Vice Admiral Richard Howe, brother of William, recruited John Montresor to assist British intelligence with his knowledge about the fort’s layout. Montresor informed Howe that the fortification was most vulnerable along its west wall, a mere earthen and wooden rampart. Howe dispatched coastal batteries to Montresor’s suggested location and instructed them to bombard the Mud Island Fort into submission. However, after four weeks of constant cannonades, the fort’s Continental defenders remained steadfast.

British forces intensified their attempts to conquer the Delaware on October 22 at the Battle of Red Bank. During the battle, 1,200 Hessian soldiers under Count Carl von Donop attempted to storm the American stronghold at Fort Mercer while the British fleet engaged the Continental flotilla. The attack failed miserably as the Hessians suffered insurmountable casualties against the superior American defenses (Von Donop himself was mortally wounded). Several British ships were also claimed as casualties of war. The HMS Augusta, a 64-gun warship, ran aground while trying to avoid river obstacles and chevaux-de-frise—wooden crates with sharp iron spears designed to puncture the hulls of ships. Stranded, the vessel was a sitting duck for the guns at Mud Island Fort, which unleashed a barrage of cannon fire. One shot managed to ignite the ship’s gun powder storage and it exploded in spectacular fashion. Fire and debris rained down and set ablaze the nearby Merlin, a 22-gun British frigate. The ship was scuttled and abandoned by her crew.

Flag Pole and Main Gate

The defense of the Delaware continued for a few more weeks following the Battle of Red Bank. On November 10, after several days of heavy rain and high tides, the British fleet was able to close its range on Mud Island and fire upon the fort. The naval barrage opened the Battle of Fort Mifflin—the largest bombardment of the American Revolution. The Americans held strong for a few days but the British were relentless in their assault. On November 15, the British fleet aimed over 220 cannons at the fort and unleashed continuous volleys at the Continentals. During the first hour of battle, over 1,000 cannonballs were fired at Mud Island and an estimated 10,000 projectiles were launched throughout the entire day. The British frigates were so close to Mud Island that British marines climbed to crow’s nests and threw hand grenades at the American soldiers huddling behind the ruins of their derelict fort.

Mud Island Fort only had ten functioning guns to respond to the British onslaught and most of them were taken out of commission early on in the engagement. The Americans were also desperately running low on ammunition and had to salvage intact British cannonballs from the fort’s walls. It was reported that “[for] each recovered cannonball that fit the fort’s guns brought a gill (four ounces) of rum to the soldier who recovered it.”

Major Simeon Thayer, acting fort commander after Colonel Smith was wounded by shrapnel, decided to evacuate the fort on the evening of November 15. While Thayer’s men crossed the Delaware to Fort Mercer, he and forty others stayed at the fort and set it ablaze. They kept the fort’s flag flying, signaling to the British that although they were defeated, they would never surrender. The British took the abandoned, smoldering ruin of a fort the following morning. Of the four hundred Continentals who defended the fort, 250 were listed as casualties. The British suffered only 37 casualties during the entire six-week bombardment.

Fort Mifflin after the Revolution

The British withdrew from Philadelphia in late June 1778 and Mud Island Fort sat abandoned for several years. It wasn’t until 1794 that Pierre Charles L’Enfant, designer of the U.S. Capitol Building, was appointed as a temporary engineer for the federal government to reconstruct the old fort. L’Enfant worked diligently but quickly exceeded his allocated budget. He was removed from the project in 1795 and replaced by French engineer Lewis Tousard. The fort was completed in 1798 and renamed Fort Mifflin after Major General Thomas Mifflin—a veteran of the Continental Army and Pennsylvania’s first governor after the Revolution.

Fort Mifflin was strategic in the defense of Philadelphia during the War of 1812. Captains Jacob Fisher and William Mitchell commanded the fort with 65 regular artillerists and several units of infantry. Though well-defended, the fort saw no action during the war as the British did not attempt to invade Philadelphia by way of the Delaware River. After the construction of Fort Delaware in 1824, Fort Mifflin was deemed “incapable of preventing enemy forces from gaining control of Philadelphia.” Federal troops left the island and the fort fell into a state of decay.

Fort Mifflin returned to service in the summer of 1863 and functioned as a military prison during the Civil War. The fort received hundreds of Confederate, Union, and civilian prisoners in its two years of operation. Like many prisons, conditions were extremely poor. Stagnant water and sewage were cesspools for disease and foul odors while captives were imprisoned in damp, overcrowded cells. As many as 216 POWs were held inside the fort at one time.

Commandant's House with Blacksmith Shop in Background

The most famous prisoner at Fort Mifflin was Private William H. Howe of the 116th Pennsylvania Volunteer Regiment. Howe abandoned his unit in December 1862 after contracting dysentery. On June 21, 1863, when enrollment officers arrived at his Perkiomenville home to arrest him for desertion, Howe opened fire and killed one of the men, Abraham Bertolet. Howe was eventually obtained and sentenced to death by hanging. He was executed at Fort Mifflin on August 26, 1864.

Fort Mifflin also saw the imprisonment of 44 civilians who were allegedly compliant in the “Fishing Creek Confederacy”—a misguided rumor of conspiracy, draft evasion, and defection in Columbia County, Pennsylvania, supposedly orchestrated by a secret Confederate fraternal organization called the Knights of the Golden Circle. On August 1, 1864, Lieutenant J. Stewart Robinson and a small party of Luzerne County soldiers were riding on horseback through Columbia County when they were ambushed by ruffians along an isolated stretch of road. Lieutenant Robinson was mortally wounded in the surprise attack (later called the Raven Creek Shooting) and blame was placed on the Knights.

Columbia County had been under scrutiny for some time with allegations of draft dodging. County leadership maintained that they were unjustly targeted to provide more than their proportional share of men on the basis of political alliance, since the population was majority Democrat. Rumors soon began to swirl that five hundred Confederate sympathizers had constructed a fort somewhere in Columbia County. The United States Army responded by launching a full investigation.

On August 13, General Davis Nash Couch and 1,000 Union troops marched through the Fishing Creek Valley and occupied the town of Bloomsburg. Frightened and upset, county residents gathered to discuss the military occupation in what is known today as the Rantz Meeting. The Army saw this assembly as a possible rebellion. On August 28, Major General George Cadwalader assumed command of the Union Army and stationed his troops in strategic points across Columbia County townships. On August 31, he authorized the arrests of one hundred citizens on the suspicion of treason after the investigation turned up no evidence of an armed conspiracy. Most detainees were released by January 1865, but some remained imprisoned until the end of the war.

After the Civil War, Fort Mifflin fell into disrepair once again. It was modernized in 1917 and prepared for active military service following the United States’ involvement in World War I. The fort served as a naval ammunition depot and stored millions of pounds of ordinance. The concentration of highly-volatile explosives so close to the city made the fort “an ever-present menace” and prompted widespread fear. The public panic was quelled after the fort was rendered inactive in 1929.

Fort Mifflin was reactivated with the onset of World War II and Korea. The fort housed several anti-aircraft guns and was the home base for Battery H of the 76th Coast Artillery Regiment—the first African American coast artillery unit in U.S. history. The fort was officially decommissioned by the federal government in 1954. While the fort itself is permanently inactive, the U.S. Army Corps of Engineers still operates a training facility outside its walls, making Fort Mifflin the oldest active military base in the United States and the only active base that predates the Declaration of Independence.

The Arsenal

Fort Mifflin is currently open to the public and costs $8 general admission for a self-guided walking tour of the grounds. There are sixteen stops on the walking tour, all of which detail the lives of soldiers, prisoners, and civilians who resided in the fort. The first stop is the old Hospital and Mess Hall (c. 1820/36) located next to the parking lot. Directly across from this building is Fort Mifflin’s North Wall. The central gate (or Sallyport) bears a marble slab over its arch, inscribed with the names John Adams and John McHenry, his Secretary of War. The stone was placed there to commemorate the fort’s completion in 1798.

To the left of the central gate is the Quartermaster’s House (c. 1843), which is the current location for the gift shop and ticket sales. Adjacent to the Quartermaster’s House is the Northeast Bastion and Casemates. The vaulted casemates below the bastion date to the late 18th century and were utilized as holding cells during the Civil War. The stone masonry on the East Wall are original to the fort’s initial construction in 1772, while the Main Gate was reconstructed in 1794.

Outside the Main Gate are the remnants of the Water Battery, which at one point contained eight 18-pound guns facing the river. Down the Nature Path around the fort’s walls are six gun platforms known as the High and Mortar Batteries (c. 1871).

Back inside the fort is a structure called the Arsenal (c. 1816). It originally served as the Guard House and Prison but was converted into small arms storage during the 1830s. The building currently houses an intriguing exhibit about the Washington-Rochambeau Trail. In the middle of the Parade Ground is the Commandant’s House, arguably the most beautiful building in the fort. The structure was designed by L’Enfant in 1796 and completed by Colonel Stephen Rochefontaine in 1798. It was originally a citadel—a place for last retreat for the fort’s soldiers—but was repurposed as a commander’s quarters in 1835.

Directly across from the Commandant’s House is the Torpedo Casemate (c. 1875), the last military structure constructed inside the fort. The casemate was used for storing and firing torpedoes. The torpedoes were launched from a small pool in the casemate floor and channeled out through a tunnel under the ramparts towards targets in the Delaware River. Next to the Torpedo Casemate is Casemate #11. This chamber was recently discovered by a maintenance man in 2006. Archeologists believe that it was used for gun powder storage and later solitary confinement for Civil War prisoners. Visitors can see perfectly-preserved graffiti on the walls, including an inscription made by William H. Howe, which suggests he was held there while awaiting his execution.

At the south end of the fort are the Artillery Shed (c. 1837) and Blacksmith Shop (c. 1790s). The large mound behind the Blacksmith Shop is the Powder Magazine (c. 1867). The magazine was constructed upon the original 1809 structure, sports five-foot walls, and has enough storage space for 1,000 barrels of gun powder.

View through the North Gate

In the northwest corner of the fort are the Soldiers’ Barracks (c. 1797) and Officers’ Quarters (c. 1814). The Officers’ Quarters were built to house four officers, each given their own apartment with two rooms—a kitchen and sleeping quarters. While the Officers’ Quarters aren’t currently accessible, the Soldiers’ Barracks are and display various exhibits detailing the Siege of Fort Mifflin and the fort’s evolution over time.

In addition to its historical pedigree, Fort Mifflin also has a reputation of being haunted. Many people have heard a “Screaming Lady” around the Officers’ Quarters. This specter is believed to be Elizabeth Pratt, who lived in the building with her husband and two children at the turn of the 19th Century. Both of her children died during a yellow fever epidemic in 1802, which caused Elizabeth to slip into a deep state of bereavement and depression. Her emotional state never fully recovered before she died of yellow fever in February 1803. Legend has it that her spirit still walks the fort mourning the loss of her children. Another ghost frequently observed is the “Man without a Face.” Many people believe this to be the spirit of William H. Howe, since his face was covered with a hood just before his execution. The faceless man is often seen roaming the casemate halls or sewing in the back corner of Casement #5.

The Philadelphia Magazine named Fort Mifflin the Most Underrated Tourist Attraction in their 2018 “Best of Philly” series. The City of Brotherly Love needs to show this place some more love. Fort Mifflin’s contributions to the trajectory of American history are too significant to be overlooked. An increase in attendance will certainly help fort administrators fund restoration projects planned for the coming decade. Whether it’s history, the paranormal, or watching airplanes fly several hundred feet overhead, Fort Mifflin has a little something for everybody.

Visit the Fort Mifflin webpage for more information on the historic site!

To learn more about the Siege of Fort Mifflin, visit the American Battlefield Trust!

For more on Fort Mifflin's paranormal activity, check out History Goes Bump!


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