The Defense of the Delaware River

Philadelphia campaign, 1777

When the British moved by sea to attack Philadelphia, they landed at the head of the Chesapeake bay at Head of Elk, and moved over land towards Philadelphia. Washington tried to stop them at Brandywine, but was out maneuvered and defeated. At Germantown he attacked and almost succeeded in destroying a part of the British army, but the attack bogged down. The British moved into Philadelphia on September 27,1777-but the Americans still controlled the Delaware River, with Fort Mifflin, on an island, and Fort Mercer at Red Bank.

The British had to have the river open to shipping. Their supplies came by sea from Britain. They would be starved out if they did not open the river before winter. They turned their attention to reducing those forts. Fort Mercer was on the NJ shore near Red Bank. Fort Mifflin was on a low island. Down stream the American's had placed obstructions in the river to prevent ships from moving up the river. They called these obstructions Cheavaux de Frize, and they were pointed logs, fastened together like tripods, weighted and sunk. Various small craft, galley gunships and barges, backed up the forts and helped prevent British small craft from using the waterways.

The American Forts were weak, not adequately manned, incomplete and poorly constructed. The "navy" that supported them was also short of crew, and found it hard to keep its craft on the river. They could not directly attack a large war ship, but could add their fire to the forts if and when the British ships tried to move upstream.

Washington, after losing so many men at Forts Washington and Lee on the Hudson a year before, was not about to risk putting that many men into a fortification that might fall again.

After a hard defense, the forts eventually fell to the seige tactics of the British, who were able to bring their over whelming naval power to bear, allowing their land forces to work cannon batteries into range, and finally battered the forts into unusability.


The British view of the Delaware Defenses; letter from Col. Bradford

From " The Spirit of Seventy-Six", edited by Henry Steele Commanger and Richard B. Morris, page 631-633

Anonymous diary recording Howe's Military operations in 1777.

September 26th, 1777- The rebels have endeavoured with vast labour and expense to stop up the navigation of the Delaware River by sinking several ranges of a kind of cheavaux de frise across the channel, to prevent our fleet from getting up to the city. A number of small islands that extend from the mouths of the Schuykill favoured this design very much. The first range runs from the Jersey shore, where there is a large battery to protect it, called Billens fort. The second range is aobut two miles higher up, nine hundred yards below Mud Island, where the rebels have a considerable work called Mifflins fort. But afterwards thinking tish as too great a distance, they sunk a couple of piers nearer to the fort including that part of the cannel and fixeda boom across, besides ahing another range of chevaux de frise ready to sink occasionally.
This kind of chevaux de frise consists of large timbers, like the main mast of a ship at the top of which are three branches armed and pointed with iron, spreading out fanwisefifteen feet asunder. The main beam is fixt at an elevation to the frame of afloat or stage, composed of vast logs, bound together as fast as possible; then covered with plank to top, and calked. When this machine is towed to its place, it is loaded with about thirty tons of stones, secured in cases, which, by taking the plugs out of the deck to admit the water into the float, sinks it down and keeps it firm and steadythe points of the branches about six or seven feet under the surface of the water, and they spread in front thirty feet. A row of these chevaux de frise are sunk sixty feet from each other and another row behind in their intervals, to form a range.
Near to Mud Island, and just above the upper chevaux de frise, the rebel fleet are lying, and consist of the Delaware frigate of twenty-eight guns, 12 and 9 pounders; the Province ship, of eighteen 9 pounders; two large briggs, of ten and eight guns; two Zebec's of ten guns each; eight smaller armed vessels; thirteen gallies, each one 18- pounder on board; tow floating batteries, of ten and nine 18-pounders, seventeen fire vessels, besides a great number of fire rafts.
High up the river near Burlington, they have tow large new frigates, the Effingham and Washington, but neither of them are manned or complete with guns.

Anonymous, "Contemporary British Account", American Antiquarian Soc. Proc., New Series, XL, 83-84


Colonel William Bradford of the Continental Army to President Wharton of the Pennsylvania Executive Council.

October 27, 1777
I have been absent from this place for some time up to Burlington, Borden Town and Trenton, after necessaries for the fleet and to hurry the commissaries in their duty. Last Monday evening was returning but when I got within two miles of Cooper's Ferry, I was informed the enemy had just landed a number of troops, which obliged me to return, by which I lost, by all accounts, one of the finest sights ever saw in these parts. My absence prevented me sending your Excellency an account of the action, but shall mention something of it now.
The 22nd instant about 4 o'clock, the enemy to the number of about 1500 appeared before the fort at Red Bank, and immediately began a most furious cannonade, for about 15 minutes, when they rushed on with great resolution to storm the fort, and got into the upper part of the old works which were not finished, and gave three cheers, thinking all was their own, but were received so warmly that they were glad to get out. They endeavoured to force thro' the abettes that were before the fort, and some even got over the ditch and were killed within the pickets; after about 40 minutes action they took to their heels and ran off with great precipitation. The enemy had about 100 killed on the field, among which were one Lieut. Colonel and four Captain. They left about 80 wounded, among which were Count Donope their commander, who lays at Red Bank with his thigh broke; and his Brigade Major wounded in three places- near thirty of their wounded are since dead. We had in the fort at Red Bank tow regiments of Rhode Island troops under command of Col. Green, consisting of about 600 men and officers. We are informed the enemy carried over to Philadelphia not less than 300 wounded. The inhabitants that saw the enemy march down say they had 14 pieces of cannon with them and returned with six. If this should be the case they must have thrown them into Timber Creek, as we have taken none.
The next day the 23rd the Augusta of 64 guns, the Roebuck of 44, two frigates and the Merlin of 18 guns came up as near as they dare to the upper chevaux de frize, when a most furious engagement ensued between the galleys and floating batteries, with the enemys ships, the fire was so incessant that by all accounts the elements seemed to be in flames; about 12 o'clock the Augusta blew up, whether by accident or from our shot is unknown, having taken fire some time before. Here presented a glorious sight befoe she blew, she laying broadside- to aground, and the flames issuing thro every port she had. The action still continued with the other ships and at three o'clock the Merlin took fire and blew up also, being aground, and then the fire soon ceased. Thus ended two glorious days.

Bradford, "Letter", Penn. Archives, 1st series, V, 707-709.

This account of the fighting for the forts comes from the diary of Jeremiah Greenman, who served from 1775 through the end of the war in 1783. His unit served first at Fort Mifflin, then at Fort Mercer.

The Greenman Diary "Diary of a Comman Soldier in the American
Revolution, 1775-1783
." An Annotated Edition of the Military Journal of Jerimiah
Greenman, by Northern Illinois Press-quotes:



S 18. this day pushed on to Hattonfield where we halted and drew sum Provision / then pushed on to Read Bank at Fort Mercy / we lodged on our tents, & very cold-

S 19. we are informed on our arrival hear that two Bomb batterys which the Enemy had erected on fort Mifflin, which they left unsupported gave an oppertunity to Colo. Smith to order a sally above & below, & the two partys supported by the gallies under Commodore Hazlewood they landed on the Beach of Province Island & stormed the Batterys, which was defended by two officers & 60 Brittish, who surrendered themselves and where carried into the Fort before the Enemy's Guards could attack the party but not before the Guns where spiked up / this small check caused the Enemy to be more cautous, & the guard of their Trenchment was afterwards so strong that it became imposable to make any other attempt. we keep very Constant Fire one [on] batterys which the Enemy was erecting to reduce for[t] Mifflin, and indeed it was very weak[,] Nothing more than a wooden fort especilly on the Side which we wanted for Defense, on the Side of New Jersey very dangerous for the Splinters-& quite unfit to support a Sige / the enclosure was of Pallsades, on the Side of Province Island; and in front opposite to Hog Island a Water Battery [of] 10-or a dozen guns, 18 pounders

/ The Enemy where not unaquainted with the Miserable Situation of the Fort and their Chife Enginear Montresor, who had been imploy'd in its Constructions, knew its weakness, & the most proper means to reduce it. Accordingly the Enemy employed a Great Number of men on Povince Island to raise more Batterys againts the fort, and covering works on the Hights in their Rear, for their Protection againts the attack that might possibly happen from Genl. Washington by the Side of Derby. / the Garrison of the Fort was quite inadequate to its extensiveness & the heavy duty, which required 1500 men in stead of the 500 which had been left for the Defense of the place & two thirds of these whare Jersey Militia / in the mean time the Enemys Batterys had got ready to play very smartly on the Fort, two bomb Battrys three 3 Gun Batteries, one of Six Guns 24 pounder between the two lower block houses, the other at the Hospital Warf of 5-24 pounders & one intermediary upon the Little Warf of Communication between Province Island and Mud Island, a Bridge of Boats was built at the lower ferry, for the Communication between the division at the Trenches & the Main camp Philadelphia / two other Batterys were likewise raised on the point of land, at the Mouth of the Schuylkill, to cut off the upper Navigation of the River, we all this time ware not inactive for we raised two 18 pounder batterys againts the Enemys Main Battery a nother of two 9 pounders to annoy the Batterys on the warf, we [had] our Magazine secured againts Shells, we endeavoured to cover ourselves againts the Shots of Province Island and diged in the inside of the Fort a Square Intrenchmt, but could not find any Means to secure againts the bombs & Carecases, except under the wall which faced the Jersey Shore, & that lay all open to the Shipping and it was very much to be feared that a Storm would be attempted, we surrounded the fort with wolf holes and Vertical Pickets to render the approach more difficult and wake up the Defenders / a sevear fire was keep by the Enemy on us, the two west block housan were ruined & the north one blew up by the fall of several Shells by which two or three men was killed & two or three more wounded, the enemy seeing this hoped to soon be in possession of the Fort & as it was very important, for their remaining in Philadelphia to have the Communication open to their Shipping.

M 20. this day we hear that Burgines Army is all captured at which this fort and fort Mercy fired 13 Cannon & all the Shipping, the Gallies went down to the Chevaux Defrizes & drove one or two Ship that was trying to get up to have fore play on the Fort / we took 6 men & a Serjt. that was in a boat going to Province Island from the Shipping.

T 21. Continuing at fort Mifflin / the duty very hard indeed

/ keep a continual fire on the Enemy & they on us with hot Shot & Shells, & building a Nother Battery to open on the fort.

W 22. this morning are informed that a party of the Enemy crossed Cooper fery last Evening and was on their way thro Haddonfield for this Fort / Came a crost this morn from Fort Mifflin [NOTE- his unit moved across to Fort Mercer] / had scarce an opportunity to git into the Fort, before a Flag came to Colo. Green, who commanded the Fort threatning to put the Garrison to [ death ? ] if he did not surrender it immediately, Colo. Green answered with disdain, that he would defend it 'till the last drop of his Blood-as soon as the Flag had returned they oppined 7 field peaces & 2 Howitzers on the fort and played very smartly for about ten moments then rushed on very Rash that even Success could not justify its temerity / they attacked on the North & South Sides, the North Side was a brea[st] work within a nother which we cut off and made the Fort small as we had but few men to man it especially the Bigness it was wen we first arrived, the Parapet was high the Dikes deep / a row of strong pallesaids sallied out from the parapit on the gate on the South Side / we had a small place big enough for eight men to fight in which overlooked all the ground round the Fort which was surrounded with double abattis /

Both of the attacks where such as was expected / the artillery & Musquetry of the fort Great Slawter / they advanced as far as the abbatis, but they could not remove it (tho sum few got over) being repulsed with great loss / they left their Command'g officer dying on the Ground in his glacis, and retreated with hurry & Confusion / they rallied in the woods and leaving thear Dead wounded & a few prisoners (which was under the walls of the Fort that could not handely retreat) in all amounting to about three hundred in our hands they returned to Philadelphia that Night-we feched in to the fort all the Wounded & dressed them shewing as [much] humanity as posable. Colo. Donop was attended with care

/ in the attack we lost 7 of our Regiment killed & I4 Wounded

/ [One] of the Killed proved to be my Capn. Shaw who was shot thro the Neck/ in all Killed and Wounded it amounted to 31
T23. the fore part of this day implying ourselves in burying the dead 73 buried in one grave 4 or 5 in [an]other & C / about 9 o'clock the Ships Eagle, Summersit, Isis, agusta, Pearl Leverpool & Several Fregates with a Galley, came up to the Chevaux de frize 500 yards from the fort, at the same time the Land Batteries & our gallies, & the Brittish S uadron engaged and one of the Most Solumest Actions commenced, that may be seen by a soldiers eye, the Spectacle was magnificent, to see at once, the river covered with Ships, four great fire ships, in a blase, floating on the Water / the Island & Main covered with Smoak & fire / part of the English Army drew up in battle array on Province Island ready to tho them selves into boats, to storm the Fort, which appeared involved with fire & was the prise of the day, the firing lasted 'till 2 o'clock PM. with [rel]entless fury. The Fort frequently fired red hot balls

/ Likewise one of the floating Batterys & either by chance or good luck one of these shot set fire the Augusta, a 64 gun Ship, the nearest to the Chevaux de frize. / [She] suddenly took fire at the stern, and in a moment She wass in a blase, & soon after blew up, with a thundering noise, before the Enemy could take out all their hands (our gallies was so nigh her at this time that several peaces fell on board of them in which one officer & a number of men [were] wounded. / a Moment after the Merlin, a 22 gun Frigate ran a shore below the Agusta nigh to this shore so that she was reached by Genl. Varnum's Battery, and as she could not be moved from the explosion, took fire & also blew up, the other ships frightened by the fate of those two retired below hog island, & the Land Batteries (which had hoised the Blody flag to warn the garrison that they were not to expect any quarter) continuing the firing from Province Island 'till Evening & then a plenty of Shells / the troops that where to storm did not attempt & the Victory yet remained to the fort and gallies.

F 24 to T 30. we hourly expect a nother visit from the Enemy, a flag went to Philadelphia / Sum hasan Doctors returned to take care of their wounded, ordered to lay on our arms-Nothing more Remarkable only the Enemy keep a very constant fire on fort Mifflin & on[c]e in a while give us a shot from a 32 pound at Hospital.

F 31. this day buried the Hasan Colo. [von Donop] who said previous to his Death I fall a Victim to my own ambition & to the avarice of my prince; but, full of thankfulness for the good treatment I have received from my generous Enemy, he was buried with the Honours of War,


S 1. this day we hung two who piloted the hasans to this fort, the Enemy crossing the Schoolkill River with a large Number of Waggons / rain & cold.

S 2 to S 9. Genl. Varnum's Brigade with about eleven hundred men went about 3 miles below this fort / Colo. Smith by his being absent by sickness was superceeded by the Barron Detrand a prusan officer [who] joined us again / The garrison by this time was very much reduced by the Dead, Wounded, Sick, and it was thought proper to relieve part of it / Some Pennsylvania & Virginia Troops took place of the Militia / the fetigue in a place where no body could sleep on account of the numerious shells, & the Garrison not having any covering was as great as the Danger [to] the Salt Provision [from] the water which was obliged to be waided into up to the knees, the cold nights & especially for the want of sleep, turned the men to the Hospital & the inclemency of the Wether almost insupportable in the Fort / in the beginning of the Sige the Garrison had opened the beach of Province Island, in ord[er] to overflow it / the Enemy filled up the Trench again, but with not sufficient Care; for a heavy Wind at NE raised the Water so high and increased its Strength so much that it brock [broke] the Beach, & almost overflowed the Island, Mud Island was drowned as much as the opposite shore, the water was two feet deep in the fort & all the barracks that yet remain where filled with it, at this time the fire was neither heavy no[r] continual_

M 10. this day the Enemy set out a new, resolving if posable to reduce the fort, knowing if it was not done they would be obliged to evacuate Philadelphia, [they] oppened three more batteries upon it & keep up an incessant fire on the Fort, all the pallisades where broken dow[n], the Diches filled up with Mud by the strong tides, Capn. Treet, who distinguished himself by his bravery, and his Lieut, was killed / the Garrison exhausted & almost reduced.

T 11. this morn cule / We burst an eighteen pounder which was got from the wreck of the agusta, and killed one Many & by the Scales & peaces of the Carrage Eighteen More where slightly wounded -
W I2. Colo. Smith was wounded and went out of the [fort] with the old Garrison, being relieved by Major Thare with sum of our men, the Enemy now began to doubt the promises of their Enginer Montresor who had constructed the Fort & had bosted at the beginning that he would reduce it in a few days, but thought all invain expecting very little from their Land Batteries.

T 13. but this morn we found a New Battery opened on the Fort, but as long as the Shipping keep below the Chevaux defrize we where in hopes, the c[h]annel between Hog Island & Tinicut had been stopped, the tides by the Chevaux defrize in the main channel had opened a new current, and the River was deeper than it was thought to be & several sail of Vessels passed the Fort with Provision to Philadelphia this Evening-

F 14. this day the Enemy sem to be very buisey on hog Island & Tinicut, we burst a 24 pounder this day that was got from the wreck of the agusta / they keep a very constant fire from the Batteries on the Fort.

S 15. this morning about 8 oClock the Enemy made a furious attack, by the River, & land / the Ships came as near to the Fort as posable in the Main Channel, & a large East Indiaman they cut down & mounted 20 24 pounders on her. She came up under the protection of the Land Batteries, behind Hog Island & anchored four yards from the Angle of the SW Battery, the Fort had been very much exposed on this side / than [then] on it, did not remain one Single Gun excep those that was dismounted / Major Thayer ordered a 32 pounder to be carried thare, which was effected with great trouble & danger, this was done before the Ship got up /

this single gun put 14 Shot into her bow but as soon as She was farly at anchor she began to play, all resistance became imposable, in 3 or 4 Broad Sides and from the tops with Cowhorn filled with Grape Shot so that it was almost imposable for a man to move without being killed,l24 not only the parapet & the carrages, but even the Iron of the guns were broken the platforms destroyed an[d] in half an hour, not a Gun in the fort was able to fire, Soon after this the Vigilant a Sloop carring 18 guns came up & anchor'd above her, played againts the Fort all the afternoon (with her Cannon & bombs) /

the gallies at the same time employed againts the ships, & shells poring from Province Island, we was not able to give them any assistance (the Ships laying so nigh the Chevaux defrize that it was almost imposable to pass with boats from us to them in this critical situation[)] / a storm was expected all the afternoon / the Garrison buried in ruins unable to retreat during the day & unwilling to do it, as long as they could expect a reingforsment, had not much expectation but to sell their selvs as dear as they could, however the Enemy did not profit this moment / Major Thayer asembled a Counsel of War in the midst of the firing a little before Night, it was imposable [to] defend the fort with so small a Force & it was determined to call for a Reingforcement from Fort Mercy & if they could not reingfors to evacuate the Fort, Before the Counsel of War broke up Major Fleury who commanded the Infentry Battery that day was wounded by the bursting of a shell & an officer of Artilery killed / at ten o clock [P.M.] no Reingforcement went from us but was sent with boats to fech them off / it was become imposable [to defend] the Fort any longer / open on all sides, without a single gun, it was no longer a Defence for the River, during the Transaction of ye day Major Talbert was wounded with a Musquet ball -Major Thayer evacuated the Fort with a Degree of fermness equal to the Bravery of his defence, he set fire to the Remains of the Barracks & with less than two hundred men carried off all the wounded & most of the Stores / he arrived hear about 12 oclock in the night.

S 16 ~ M 17. this morning we had a few 32 pounder sent among us from the Hospital Battery, the Colours was left flying which we saw in the morning halled down by the Enemy-the Field officers holding a Counsel of War, which we suppose is concerning the evacuation of this place_

T 18 ~ W 19. we hear a number of the Enemy is marching for this post, at 10 oclock at night we received orders to march & struck our tents, loading them into waggons & took what provision we liked / destroyed the remainder, then proceeded on to Haddon Field where we made a halt.

T 20. Continuing in haddonfield / a party of men sent back to ye fort with a Serjeant to stay thair till ye enemy appeared then to blow ye fort up / Sum waggons ariv'd this afternoon with sum clothes / a quanterty of flower came in from the fort / order'd to lay on our arms.

F 21. this morn about 4 o clock slung our packs march[t] from haddon came to morestown ware made a small halt / then proceded on as far as moun halle ware we made a halt / lodged in a barn & very cold.

S 22 ~ S 23. Continuing in mount hole / this day ye biger part of ye Rigement drawed Clothes &c / we ware ordered to be in ready ness for a march / about ten oClock order'd to sling our packs / we marcht to the uper end of the town ware we made a halt / was orderd to bring in the returns of each company what men was fit for duty. then return'd to our quarters again / drawed 50 rounds of carteriges & C.



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