British Open Hostilities in Long Siege on Fort Mifflin, September 27, 1777

The British Army was in possession of Philadelphia, but the communication was not open with their fleet, and General Washington in evacuating the city had placed a garrison in Fort Mifflin, not as strong as the importance and exigencies of the place required, but such as the situation of his army could afford.

Fort Mifflin was nothing more than a wooden fort with an inclosure of palisades. It was situated on Mud Island, on the Pennsylvania side of the Delaware River. The small Pennsylvania fleet was in command of Commodore John Hazlewood.

The British were not unacquainted with the miserable situation of the fort and knew its weaknesses and the best means to reduce it.

On September 27 the enemy on Providence Island opened two mortars 671and three heavy guns against the southeast blockhouse. That left these batteries unsupported, which gave an opportunity for Colonel Smith to order a sally above and below.

Two parties supported by the galleys under Commodore Hazlewood landed on the beach of Providence Island and stormed the battery, which was defended by two officers and sixty British, who surrendered themselves. They were carried into the fort before the enemy’s guards could attack the Americans, but not before the guns were spiked.

From October 10 to the 21st a severe fire was kept up; the two west blockhouses were ruined and the north one blown up by the fall of several shells.

The enemy, seeing the breaches made to the palisades, hoped to gain possession of the fort, and as it was very important for their remaining in Philadelphia that the communication be open, they determined a general storm on Mud Island October 22.

Previous to it, in the evening of the 21st, the Hessian brigade crossed at Cooper’s Ferry to storm Fort Mercer, on the Jersey shore about 1500 yards northeast of Fort Mifflin and up the river. The attack was so rash that even success could not justify its temerity.

Before the storm of the fort was attempted Colonel Donop sent a flag to Colonel Christopher Green, who commanded the fort, threatening to put the garrison to the sword if he did not surrender it immediately. Colonel Green answered with disdain, saying he would defend it till the last drop of his blood. About an hour before night the attack was begun on the north and south side.

Both the British attacks were expected. The artillery and musketry of the fort and the heavy guns of the galleys poured grapeshot and cannon balls upon them and made great slaughter. They advanced as far as the abattis, and being repulsed with great loss, they left their commanding officer dying and retreated with hurry and confusion. They rallied in the woods, and leaving their wounded and dead, about 300, in the hands of the victors, retired to Philadelphia the same night.

Colonel Green and the officers who had displayed so much courage in repulsing the enemy, treated the wounded with much humanity. Colonel Donop was attended with the greatest care, but he died a few days after the action, and was buried with the honors of war.

The morning after the attack on Fort Mercer it became Fort Mifflin’s turn. On the 22d, about 9 o’clock, the ships Eagle, Somerset, Isis, Augusta, Pearl, Liverpool and several frigates, with a galley, came up to the chevaux de frise, 500 yards from the fort. At the same time the land batteries, the fort batteries and the American galleys and the British squadron engaged.

The firing continued until noon with relentless fury; the fort frequently fired red-hot balls, one of which struck the Augusta, a sixty-four-gun ship, she took fire, and in a moment was ablaze, and soon 672after blew up with a thundering noise, before the enemy could take out all their hands.

A moment after, the Merlin, a twenty-two-gun frigate, ran ashore below the Augusta, and as she could not be removed before the explosion, took fire and also blew up.

The other ships, frightened by the fate of these two, retired below Hog Island; and the land batteries, which had hoisted the bloody flag, to warn the garrison that they were not to expect any quarter, continued their fighting until evening.

The weakened garrison had been re-inforced by Pennsylvania and Virginia troops, but Colonel Smith found the garrison in great danger from fatigue and salt provisions, the water they had to wade through, the cold nights and constant firing by the enemy turned many men to the hospital.

The enemy suffered also from the inclemency of the weather, and the overflowing of the island. The water was two feet deep in their fort.

The British, believing they must evacuate Philadelphia or take the fort, made new batteries, and on November 8 kept up an incessant fire.

All the palisades were broken down and the block houses ruined. The ditch filled up with mud. Captain Treat and his lieutenant were killed. Colonel Smith was wounded and the garrison nearly exhausted.

Major Thayer with some New England troops relieved the garrison. Major Fleury would not be relieved and remained with the garrison.

On November 15 the enemy made a furious attack by the river and land and floating batteries on the fort.

The ships came as near the fort as possible in the main channel, and the Vigilant, carrying 24-pounders, came up under the protection of the land batteries, behind Hog Island, and anchored forty yards from the angle of the battery.

Fort Mifflin had been so much exposed on that side that on it did not remain a single gun. Major Thayer ordered the 32-pounder to be carried there. Before the Vigilant began to fire that single gun put fourteen shots in her board. But as soon as she was at anchor and began to play all resistance became impossible.

In three or four broadsides not only the parapet and the carriages but even the irons of the guns themselves were broken, and in half an hour not a gun in the fort was able to fire.

Another sloop of war joined the Vigilant and played against the fort all the afternoon.

The garrison was buried in ruins, unable to retreat during the day and unwilling to do it as long as they could expect re-enforcements, had not any expectation but to sell their lives dearly as they could.

It was impossible to defend the fort with so small a force, and Major Thayer called for re-enforcements from Fort Mercer or he must evacuate 673the fort. At that moment Major Fleury and Major Talbot were wounded and another officer of artillery killed.

At 10 o’clock at night, as no re-enforcements had arrived from New Jersey, it was impossible to defend the fort any longer.

Major Thayer evacuated the fort with a degree of firmness equal to the bravery of his defense. He set fire to the remains, and with less than 200 men, having carried off all the wounded, he arrived at Fort Mercer about 1 o’clock in the morning, being the last man to march out of the fort.

The British took possession of Fort Mifflin half an hour after the Americans left it.