Fort Mifflin: The Unyielding Bastion That Saved a Revolution
PHILADELPHIA, PA – Along the muddy banks of the Delaware River, just south of Philadelphia’s bustling port, lies a quiet testament to American resilience. Weathered brick and stone fortifications, now largely reclaimed by nature and the passage of time, whisper tales of a brutal autumn in 1777. This is Fort Mifflin, an unassuming yet profoundly significant landmark often overshadowed by the grander narratives of the American Revolution, yet one that arguably saved the fledgling nation.
Known to its defenders as "Mud Island Fort" and to later generations as the "Gibraltar of the Delaware," Fort Mifflin stood as the final, desperate bulwark against a British invasion that threatened to sever the head from the body of the Continental Army and extinguish the flame of independence. Its story is one of unimaginable hardship, unwavering courage, and a strategic sacrifice that bought George Washington precious time, enabling the survival of the revolution.
The Strategic Imperative
Following their decisive victory at the Battle of Brandywine and the subsequent occupation of Philadelphia in September 1777, the British forces under General Sir William Howe found themselves in a precarious position. While they held the American capital, their army of 15,000 men was cut off from vital supplies. The deep-water port of Philadelphia, essential for resupply by the Royal Navy, was inaccessible due to an ingenious and deadly defense system established by the Americans.
This system comprised two key components: Fort Mercer on the New Jersey side of the Delaware River and Fort Mifflin on Mud Island, a small, swampy islet in the middle of the river. Between these forts, the Americans had sunk a series of massive wooden obstacles known as chevaux de frise – sharpened logs tipped with iron spikes, designed to rip open the hulls of any ship attempting to pass. To control the river, the Americans also deployed a small but formidable fleet of gunboats, floating batteries, and galleys, commanded by Commodore John Hazelwood.
For Howe, breaking this blockade was paramount. Without a secure supply line, his army in Philadelphia would eventually starve or be forced to retreat. The fate of the British occupation, and indeed the entire war effort, hinged on opening the Delaware.
The Crucible of Courage: The Siege Begins
The British launched their initial assault on October 22, 1777, focusing on Fort Mercer, which was valiantly defended by Colonel Christopher Greene and his Rhode Island regiment, including a significant number of African American soldiers. The Hessian forces, hired German mercenaries fighting for the British, suffered a devastating defeat, losing hundreds of men and two of their commanders. This setback only hardened Howe’s resolve to dismantle the American river defenses.
With Fort Mercer proving impregnable from a land assault, the full might of the British land and naval forces turned their attention to Fort Mifflin. It was a less imposing structure than Mercer, built hastily and primarily of earthworks, timber, and fascines (bundles of sticks). Its isolation on a muddy island made it vulnerable, but also made it difficult for the British to approach directly.
On November 10, 1777, the grand bombardment of Fort Mifflin began. For six relentless days and nights, the British unleashed an unprecedented barrage of cannonballs, mortar shells, and grapeshot from batteries established on the Pennsylvania mainland and from their powerful warships on the river. The defenders of Fort Mifflin, a small garrison of approximately 400 men from various Continental Army regiments and Pennsylvania militia, faced an overwhelming onslaught.
A Hell on Earth
Conditions within the fort quickly devolved into a living nightmare. The constant thunder of cannons, the whistling of incoming shells, and the screams of the wounded became the soundtrack of their existence. The fort’s wooden structures were splintered, its earthworks crumbled, and the meager casemates (bomb-proof shelters) offered little true protection.
"It was a scene of unparalleled destruction," wrote one contemporary observer, describing the fort as "a heap of ruins, untenable in any part." Accounts from the time speak of men fighting amidst the debris, dodging falling timbers, and suffocating in the acrid smoke of gunpowder. Disease, particularly smallpox and scurvy, was rampant, weakening the already exhausted and undernourished garrison. Food and fresh water were scarce, and the freezing November winds offered no respite.
Despite the horrific conditions, the defenders of Fort Mifflin, initially commanded by Colonel Samuel Smith and later by the indomitable Major Simeon Thayer, refused to yield. They returned fire with every working cannon they had, their shells often finding their mark on the British ships and land batteries. The Americans even managed to sink two major British warships, the HMS Augusta and the HMS Merlin, which ran aground during the battle and exploded, a temporary but significant victory for the beleaguered defenders.
The Final Stand and Strategic Retreat
As the siege wore on, the British intensified their bombardment. On November 15, they brought up a floating battery, the Vigilant, armed with 32-pound cannons, which anchored just yards from the fort’s shattered walls. The point-blank fire ripped through what little remained of Fort Mifflin. Casualties mounted, and the fort’s medical facilities, already overwhelmed, were virtually non-existent.
By the evening of November 15, Fort Mifflin was a moonscape of craters and rubble. Its walls were breached, its guns dismounted, and its garrison decimated. With fewer than 100 able-bodied men remaining, and facing inevitable annihilation, Major Thayer received orders from General Nathanael Greene to evacuate. Under the cover of darkness, the tattered remnants of the garrison slipped across the river to Fort Mercer, leaving behind a fort that was no more than a pile of ruins.
The British occupied Fort Mifflin on November 16. It was a pyrrhic victory. The capture of Fort Mifflin, and subsequently Fort Mercer (which was evacuated shortly thereafter), allowed the Royal Navy to finally clear the chevaux de frise and open the Delaware River. However, this success came at a steep price for the British in terms of time.
The Unsung Victory
The defense of Fort Mifflin, lasting an astonishing six weeks from the first British assaults on the river defenses, was a strategic triumph for the Americans, despite the fort’s ultimate fall. This prolonged resistance had a profound impact on the course of the war.
"The obstinate defense of Fort Mifflin delayed General Howe’s operations until the severe weather set in," observed a British officer, acknowledging the crucial time lost. This delay was exactly what George Washington needed. While the British were bogged down in their efforts to open the Delaware, Washington was able to consolidate his forces and move them to their winter encampment at Valley Forge.
Had Fort Mifflin fallen quickly, Howe could have potentially moved his well-supplied army from Philadelphia and launched a devastating winter campaign against Washington’s vulnerable forces, perhaps even destroying the Continental Army before it could recover. Instead, the Fort Mifflin defenders, through their incredible sacrifice, bought Washington the precious weeks he needed to establish a defensible position, regroup, and begin the arduous training that would transform his army into a more formidable fighting force.
Historians often refer to Fort Mifflin as the "Gibraltar of the Delaware" because, like the famous British stronghold, it held out against overwhelming odds and was ultimately evacuated rather than surrendered. Its defense became a symbol of American resolve and a testament to the fact that even in defeat, there can be strategic victory.
Fort Mifflin Today: A Living Monument
Today, Fort Mifflin stands as a National Historic Landmark, meticulously preserved and open to the public. Visitors can walk through the restored casemates, see the reconstructed barracks, and stand on the earthworks where so many Americans fought and died. The scars of the 1777 bombardment are still visible in some of the original brickwork.
The site offers a tangible connection to a pivotal moment in American history, allowing one to almost hear the echoes of cannon fire and the cries of soldiers. Beyond its historical significance, Fort Mifflin also holds a reputation for being one of America’s most haunted sites, with numerous accounts of paranormal activity attributed to the spirits of those who perished within its walls. While these tales add an intriguing layer for some, they ultimately serve to highlight the intense human drama that unfolded here.
Fort Mifflin is not just a collection of old buildings; it is a living monument to the bravery of ordinary men who, against all odds, faced down the might of the British Empire. Their sacrifice, their endurance, and their strategic delay in the autumn of 1777 ensured that the promise of independence had a fighting chance to endure. It reminds us that even in the face of overwhelming power, the unyielding spirit of a few can alter the course of history. As the Delaware River flows silently past its walls, Fort Mifflin stands as a timeless sentinel, guarding the memory of a pivotal moment when the very survival of a nation hung by a thread, and courage prevailed.
