Written by Michael J. Perullo
12! 18!! 24!!! 32!!!! These numbers inspired fright in 1777 because they were the weight in pounds of typical cannon balls fired at Fort Mifflin in 1777 by the British Royal Navy! Fort Mifflin, built over generations on Mud Island in the Delaware River just south of Philadelphia, was the site of the heaviest bombardment of any place in America during the American Revolution. Beginning on November 10, 1777 (coincidentally, the second-year anniversary of the formation of the United States Marine Corps at Tun Tavern in Philadelphia), the British Royal Navy unleashed five days of withering cannon fire on the Fort. TEN-THOUSAND cannon balls were fired in less than 120 hours, and at its peak, 1,000 cannon balls were fired in a single hour at the four-hundred-six men inside Fort Mifflin. The men only abandoned the fort when THEY ran out of ammunition for their ten cannons! The American Defenders left the “Fort Mifflin Flag” flying when they abandoned the fort early on the morning of November 15, 1777. The purpose of the defense of Fort Mifflin was ‘delay’; here is the story.
The Fort Mifflin flag with its unique pattern of red, white and blue stripes. No other known flag used this specific pattern. ©Shorepine
Today, Fort Mifflin is no longer on an island, but on the former Mud Island which was infilled and connected to land near to the eastern end of Philadelphia International Airport; you can see it from I-95! But in 1777, during the American Revolution, it provided the key western shore defense of the Delaware River just (about six miles) below Philadelphia, which, as you can imagine, was a much smaller city in 1777; although with ~37,000 inhabitants, it was the most populated city in the Colonies. The British Royal Navy was trying to sail 92 miles up the Delaware River from the Atlantic Ocean to resupply their troops and occupied Philadelphia before winter. Today, we really don’t think too much about Philadelphia as an ocean-accessible port, but it is like New Orleans which is a similar 95 miles up from the open Gulf of America. During the Revolution, the British needed to bring supplies and ground forces in by ship, and access to the Delaware River at Philadelphia and points north and south was paramount.
At the most critical time for Fort Mifflin, the British were consolidating their wins in Philadelphia, New York and Long Island. During the Battle of Brandywine Creek, General George Washington fought the British Army of General Sir William Howe on September 11(!), 1777; Washington lost this battle, and was beginning his retreat and consolidation of forces during which was to be remembered as a fierce winter of depravity at Valley Forge. (When Martha Washington visited, she was so dismayed at the conditions of and for the men, she arranged for the purchase of 2,000 pairs of woolen socks for the men from her own money.) General Washington needed time to consolidate his existing forces, and to provide a base for the recruitment of new soldiers during the winter of 1777-78. Fort Mifflin was the protection to the south of British occupied Philadelphia; the British desperately needed resupply from their massive and powerful navy not only of soldiers (“Redcoats”), but every conceivable supply. Fort Mifflin was the delay mechanism intended to slow the British from reaching Philadelphia's port.
At the time of the November 1777 battle, General Howe’s resupply ships were about 15 miles below Philadelphia, and were critical to retaining local and area gains made by Howe and his troops. Yes, this was the same General Howe who was pushed out of Boston on “Evacuation Day” (March 17, 1777), which Bostonians still conflate with St. Patrick’s Day. Fort Mifflin had only ten cannons, but was buttressed by Fort Mercer ~2,000 yards (about 1.1 miles) across the Delaware River in New Jersey. The idea was a pincer action to choke the British Navy in a relatively narrow and shallow channel in the river. It worked, as Washington had previously issued orders that the fort was to be held “to the last extremity”!
Beginning in September 1777, the 406 men at Fort Mifflin did hold off the British ships from advancing upriver towards Philadelphia. There were 250 ships ferrying 2,000 Redcoats, and thousands of tons of supplies destined for the enemy that needed to be delayed and/or stopped. Actions by the men stationed at Fort Mifflin provided the time Washington needed to fight at White Marsh and regroup at Valley Forge.
A map of the Fort Mifflin area in 1777 vs. today: once positioned on Mud Island, the fort (outlined in red) is now surrounded by infill on three sides and sits adjacent to Philadelphia International Airport. ©OpenMaps.
Can you imagine being able to see the Fort Mifflin Flag from Philadelphia six miles distant?! Imagine occupiers encountering this flag up close while Americans saw the flag from their occupied city. Seeing the flag was possible then; today, no one really knows its true dimensions. In fact, the Fort Mifflin Flag was borrowed from an American naval ship sent to menace British shipping traffic on the Delaware River. Originally in use as a Continental Navy Jack, it had no union, but had 13 red, white and blue stripes mesmerizingly arranged in a pattern seen on no other flag. Similar and dissimilar to the Serapis Flag, the Fort Mifflin Flag had thirteen stripes, which starting from the top were four sets of red, white, and then blue, and then one red stripe along the bottom edge. What a pattern! Recall that Betsy Ross lived nearby in town, and the Continental Congress passed the Flag Act of 1777 on June 14. Back then, there were no factories turning out new Betsy Ross Flags! Three months later, the men at the fort only had this ‘borrowed’ Navy Jack to signal to all that the fort was in American hands; it was their only flag. So important was this flag to the fort, that when its mast was shot away during the siege, two men were killed hoisting it back up.
The Fort Mifflin Flag signifies COMMITMENT, DUTY, GRIT, TENACITY, RESISTANCE, and AMERICAN RESOLVE UNDER EXTREME DURESS!
The siege of Fort Mifflin began on October 4, and lasted until the men ran out of cannon shot on the morning of November 15, 1777. The Fort Mifflin garrison-sized flag flew all during this time. To this day, no one has seen the actual flag flown since the battle. We know what the flag may have looked like from the “1777 Montresor Map” of the defenses of Philadelphia which has a small colorized image of the flag. Historians have debated for years whether the image on this map represented the true flag, as the stripe pattern on the map image was different than the stripe pattern in common usage today.
As mentioned, from top to bottom, the Fort Mifflin Flag is known to have four groups of Red, White and Blue stripes, followed by a single Red stripe along the bottom. But the Montresor map showed stripes of Blue-White-Red, White-Red-Blue, White-Red-Blue, and White-Red-White-Blue! Some have attributed the painted image on the map to artistic license, and others have tried to compare the stripe pattern to the seemingly confusing pattern later used on the Serapis Flag from 1779.
Fort Mifflin wasn’t actually called Fort Mifflin until 1795 when it was renamed for Thomas Mifflin, a Continental Army Officer, and first post-Revolution Pennsylvania Governor. It was originally called Fort Island Battery, and was also known as Mud Island Fort. Even Mud Island was sometimes called Deep Water Island. A fort was originally begun on the site in 1681 for colonial defense. The fort as it is known today for its Revolutionary role, was originally commissioned in 1771, and took years to build and outfit as it was used during the siege of 1777. The bombed fort was rebuilt in 1794, and used until 1962 when it was decommissioned for active-duty infantry and artillery. The decommissioned section of the fort was deeded to the City of Philadelphia, but a portion of the fort’s grounds have been used continuously through this day by the U.S. Army Corps of Engineers. It is considered to be the oldest fort still in use by the military.
The Fort Mifflin Flag still flies above the fort today, which is preserved as a National Historic Landmark. Photo by Larry Lamb.
It is interesting to note that traditionally as Colonists arrived from Europe in what would become America, most settlements began with fortification for settler protection. However, Quakers in Pennsylvania founded the only settlements without such fortifications, as they rejected the military, and sought peace and trade with local Indians. Philadelphia became the largest city in the Colonies partly because of this posture, as precious resources were not expended on defensive works.
Things started to change during King George’s War of 1744-1748. Maybe you’ve heard of the then 38-year-old Benjamin Franklin, who was worried that the city’s majority of Quaker legislators would not engage in any military defense of Philadelphia or fund any ships of war. Franklin raised money himself to build earthwork defenses around the city and to buy cannon. Franklin’s work was left derelict after the King George War. However, the French and Indian war of the 1750s renewed interest in these defenses; it wasn’t until the early 1770s when plans for a fort on Mud Island were established.
In 1771, Philadelphia was the largest port in British America, and it was Pennsylvania’s governor John Penn who asked British General Thomas Gage to help with the defense of the city. It was Gage who tasked Captain John Montresor of the British Corps of Engineers to propose designs for city defense. Isn’t it ironic that the British designed and built the first works on Mud Island which would become known as Fort Mifflin?
The British never fully completed the works on Mud Island. It wasn’t until after the Declaration of Independence was signed that Franklin, via his Committee of Public Safety, rushed to finish Fort Mifflin (Mud Island Fort) before Christmas 1776. The Committee also built Fort Mercer across the river in New Jersey. The men who built these forts also built major underwater obstacles to thwart ship travel to those unfamiliar with their placement. These were staggering construction undertakings. These constructors built 30’ square boxes filled with 40 tons of rock under flowing river water and topped them with ‘chevaux de frise’ obstacles. These were spiked timbers with iron-tipped spikes facing downstream, and underwater. The system was genius as it allowed ships to pass if they understood where these navigation hazards were positioned. How many of the 250 ships participating in the siege of Fort Mifflin were impaled by these devices is not known. The purpose of the siege was to open a supply line for the British. Much of Fort Mifflin was destroyed in the five-day barrage in what became known at the Battle of Mud Island. Imagine thinking it was a good idea to fire 10,000 cannon balls at Mud Island Fort!
The delay in British resupply, and the cost of their bombardment facilitated the repositioning of Washington’s forces, and living to fight another day. 250 of the 406 men stationed at Mud Island during the siege were either killed or wounded. These wounded men, and their fallen comrades were all evacuated to Philadelphia for treatment and burial. After November 15, 1777, Mud Island and Fort Mifflin never saw military action again, and it lay derelict until 1793 when Pierre L’Enfant (architect of Washington, D.C.) was engaged in rebuilding the fort, which was still very heavily fortified as the War of 1812 began. During the Civil War, it held Confederate prisoners of war, and during World War II, the Army mounted anti-aircraft guns to protect the nearby Naval Ammunition Storage Depot and the Philadelphia Naval Shipyard.
What holds true for the American Flag is also true for the Fort Mifflin Flag, that it was and is recognized as a symbol of patriotism. Federal courts have said that the American Flag “is the symbol of our national unity, transcending all internal differences however large, within the framework of our Constitution”. This sounds like something Abraham Lincoln himself might have said. The Fort Mifflin Flag is special because it was elemental in the birth of a new nation; this borrowed Navy Jack, then visible for miles, signaled that this place was American-held, and that the King’s men shall not pass without great difficulty.
Again, the Fort Mifflin flag signifies:
COMMITMENT,
DUTY,
GRIT,
TENACITY,
RESISTANCE, and
AMERICAN RESOLVE UNDER EXTREME DURESS!
Let us remember Fort Mifflin and her defenders in our commemorative thoughts during America’s 250th year and beyond.
Main photo above by R'Iyeh Imaging
