Fortifying Philadelphia: A Chain of Redoubts and Floating Bridges

A Survey of the City of Philadelphia, 16 November 1777, by John Montresor. Source: Library of Congress

On August 25, 1777 General William Howe with 17,000 men landed at Head of Elk, Maryland; he was 57 miles south of the city of Philadelphia. Over the next month, he battled the Continental Army at Brandywine Creek and the South Valley Hills before marching into Philadelphia on September 26.

A Survey of the City of Philadelphia, 16 November 1777, by John Montresor. Source: Library of Congress
A Survey of the City of Philadelphia, 16 November 1777, by John Montresor. Source: Library of Congress

Because he planned to spend the winter in the city, he needed to be guaranteed the delivery of supplies before the Delaware River froze. Before this could occur his army had to accomplish several things as quickly as possible: take control of Chester and Billingsport, the two towns on the Delaware between Head of Elk and Philadelphia; subdue the American forces in Fort Mifflin and Fort Mercer, the two forts guarding the approach to Philadelphia; and remove the Chevaux de Frise that the colonists had secured to the Delaware riverbed. Amazingly, all of this was accomplished between October 1 and December 1, 1777.

To protect the city from an attack by Washington and the Continental Army, General Howe ordered his chief engineer, Captain John Montresor, to build a chain of 10 redoubts across a 2 ½ mile stretch of land to the north and 2 floating bridges across the Schuylkill River to the west. Because many of the soldiers were involved in the taking of Fort Mifflin and Fort Mercer, inhabitants from the city had to be hired to help build the redoubts and floating bridges. The story of this construction project has been left to us in the diaries and journals of those who were there.

September 27-29: “This afternoon began to reconnoiter the heights near this city, for forming the defense of it, by Field Works, running from the Schuylkill to the Delaware Rivers. This I [Captain John Montresor] was given to understand was our present grand object … I attended him [General Howe] and settled for the payment of the Inhabitants that could be procured to work. Allowance 8 shillings a day to four and eight pence per day … We found in the city about 50 Boats of all sorts and procured a Durham boat from Frankford creek that will hold 100 men”;[1] “Early this morning I begun on fixing the Situation for forming a chain of redoubts for the defense of the city. This afternoon I attended Lord Cornwallis in viewing the Position I had fixed on for the works … North of the city.”[2] “Engineers begun to mark out the defences … several new boats discovered.”[3]

“A Survey of the City of Philadelphia & it’s Environs … & several Batteries & Works constructed thereon, 15 December 1777” Surveyed and drawn by P. Nicole; Annotated by John Montresor. Source: Library of Congress
“A Survey of the City of Philadelphia & it’s Environs … & several Batteries & Works constructed thereon, 15 December 1777” Surveyed and drawn by P. Nicole; Annotated by John Montresor. Source: Library of Congress

October 1-3: “Several Scows, Flat Boats and others found and brought to Town that were hid in the marshes.”[4] “At 10 this morning signed the order for Provisions for 340 Inhabitants to work on the redoubts … At 11 this morning orders from the General by Captain Mulcaster for me to attend principally to the 2 outer faces of all the Redoubts first & to begin immediately on the Schuylkill and works from it.”[5] “[E]ach redoubt was to be occupied by a captain, two lieutenants, and fifty men, who were relieved each day.”[6]

To hurry construction of the bridge, huts were built nearby to house the workers who would otherwise have had to proceed each morning from their homes or regimental encampments.

October 17-20: “This day principally employed … in transporting the materials for the Bridge … at Grey’s ferry.”[7] “The detachment from Wilmington and … Chester arrived on the opposite side at 2 o’clock P.M … With the detachment arrived the Engineer.”[8] “The Commander-in-Chief with the army marched from Germantown to the heights North of Philadelphia … and encamped in the rear of the 10 redoubts.” [9] “The ten newly erected but not completed redoubts which lie scattered from the Delaware to the Schuylkill are in front of our camp.”[10] Similar accounts are related by Captain Johann Ewald, Lieutenant General Archibald Robertson, Lieutenant Colonel John Simcoe, and Major John Andre.[11] “At just past 10 this morning, the Engineers finished the Floating Bridge across Schuylkill upwards of 400 feet.”[12]

The pontoon bridges were made with flat-bottomed boats, to which were attached joists and floor planks. The bridges served multiple purposes: they facilitated the movement of supplies, the movement of information, and the movement of troops.

October 21-24: “Began on the Tete de Pont [a defensive work at the end of the bridge on the enemy’s side] on the west side of the Schuylkill …“[13] “At 3 o’clock P.M. the works for the tete de pont at Gray’s Ferry ordered to be stopt and the Detacht. … bridge to be taken up and carried to Middle Ferry.”[14] “This night made work for 30 men on each side of Middle Ferry house to cover the workmen making the Floating Bridge.”[15] “finished 3 Lodgments for 40 men each as a Tete de pont opposite on West Side of Schuylkill. Began this morning to lay the Bridge and Middle Ferry and I completed it this afternoon.”[16]

October 28-30: “At 2 P. M. the floating Bridge at Middle Ferry was carried down the Schuylkill by the N. E. Stormy High tide and rapid stream and Ebb together.”[17]

“The same Tide which troubled us produced greater Derangement in the projects of the Enemy. Their Bridge over the Schuylkill was broke by it, and 12 of their Boats six of them large ones, … drifted to us.“[18] “This night the Rebels set fire to several of our boats that formed our Bridge at Middle Ferry.”[19]

“Lower Bridge on Schuylkill at Gray’s Ferry.” Woodcut attributed to Charles Wilson Peale. Source: Columbian Magazine, August 1787
“Lower Bridge on Schuylkill at Gray’s Ferry.”
Woodcut attributed to Charles Wilson Peale. Source: Columbian Magazine, August 1787

November 5-19: “Began on another floating bridge across the Schuylkill at Middle Ferry …. “[20] “Brought up 20 anchors for the Bridge.”[21] “Bridge across Schuylkill … passable for Horse and foot.”[22] “Bridge across Middle Ferry … finished.”[23] “The 1st grenadiers, 1st light infantry and 33rd … crossed the Schuylkill at the bridge and marched under the command of Lord Cornwallis to Chester.”[24] “… our well fortified camp, the right flank of which is anchored on the Delaware and the left on the Schuylkill. In front we have 10 well placed redoubts.”[25] “They have thrown up very strong lines across – from River to river … ten … very strong redoubts, ditched, friezed, picketed and abbatised; every one which cross fire and flank their lines.”[26]

The redoubts were “at a distance of four hundred Yards from each other”[27], connected by a dense abatis.

December 1-10:Return of the Number and Nature of Ordnance in the severall Redoubts”[28] Column 1 identifies the redoubt, columns 2 thru 7 identify the cannonball size, the material the cannon was made of and the number of cannon, and column 8 identifies howitzers:


“In each of the ten redoubts, guard houses are being built. They are fully supplied with artillery and ammunition.”[29] “A pontoon bridge was laid across the Schuylkill at Grey’s Ferry.”[30]

December 22: “Sir Wm. Howe moved out from Philadelphia with 7000 men across the Schuylkill over the 2 floating bridges and so to Darby leaving Lt. General Kniphuysen [with 6000 men] in command at Philadelphia.”[31]

Darby was three miles west of the Schuylkill River. “A scanty supply of forage and fresh food … induced General Howe to cross the Schuylkill on the 22nd with a larger part of the army and encamp on the left of the main road this side of Derby in a line four and a half miles long … “[32] His force included three jäger companies with half of them mounted, two battalions of light infantry, British and Hessian grenadiers, four troops of light dragoons, the Anspach Brigade and 200 wagons. Washington prepared a plan for a Christmas day attack, which will be discussed in a future article, but when Howe pulled his forces back to the Schuylkill the plan was no longer viable.

December 28-30: “At About 8 in the morning the army marched toward Philadelphia. The Light infantry took post above the bridge at Grey’s until it was taken up.”[33] “The several brigades daily move into the eleven redoubts along the line from their quarters. The redoubts are numbered beginning on the Delaware, the 1st, 2nd, and 3rd are occupied by the English Guards and the Queen’s Rangers, the 4th by the 1st English Brigade, the 5th by the 2nd, the 6th by the 4th, the 7th by the 3rd, the 8th, by the 5th and the 2nd Battalion of Anspachers, the 9th by Stirm’s brigade, the 10th by Woellwarth’s, and the 11th by the Hessian grenadiers.”[34]

The redoubts when completed ran from the mouth of Conoquonoque Creek near Willow Street on the Delaware River to the “Upper Ferry” on the Schuylkill River. They were numbered according to their placement along the chain; their locations, identified by current street names, were as follows:

#1 was located near Green and Oak Streets on the Delaware River;

#2 was located west of North Second and Noble Streets;

#3 was located between North Fifth and Sixth Streets and Noble and Buttonwood Streets;

#4 was located on North Eighth Street between Noble and Buttonwood Streets;

#5 was located on North Tenth Street between Buttonwood and Pleasant Streets;

#6 was located on Buttonwood Street between North 13th Street and North Road;

#7 was located on North Schuylkill Eighth Street between Pennsylvania Ave. and Hamilton Street;

#8 was located on North Schuylkill Fifth Street and Pennsylvania Ave;

#9 was located on North Schuylkill Second Street near Callowhill Street; and

#10 was located on the Schuylkill River at the “Upper Ferry”, near present-day West River Drive and Spring Garden Street.[35]

Two additional redoubts were constructed about one-eighth of a mile in advance of this chain of ten to watch the Wissahickon and Germantown Roads. Also a dam was constructed across the Cohocksink Creek causing the nearby meadows to be covered with water. This formed a water barrier immediately to the west of Redoubt #1.

March 19: “Began to repair the Parapets at the Redoubts.”[36]

April 20-24: “ Engineers marked out two advanced works in the Lines.”[37]; “Begun on our advanced works in Front of the lines consisting of 400 men for the working party. Two semi-circular Redoubts, one for 100 men to the left one for 50 in the right.”[38] “Two redoubts are to be constructed about 600 paces in front of our lines on well selected, commanding heights toward Germantown.”[39]

May 12-14: “Some of the redoubts were dismantled without my knowledge, rather unmilitary.”[40]

June 3-18: “Redoubts dismantled of their Field train (artillery) and some iron … 12 Pounders and some old ones, sent all without my knowledge.”[41] “This morning early the Kings Troops evacuated the city of Philadelphia and the several redoubts and works that form its defences and retired by land to Gloucester Point 4 miles below it on the Pennsylvania Shore …”[42]

Montresor’s extensive fortifications north of Philadelphia were never attacked during the British stay. When the British departed in June of 1778, they dismantled or abandoned the works that had taken so much effort to construct. The Historical Society of Pennsylvania has on display the entire “Plan of the English Lines Near Philadelphia 1777.” It was drawn by Lewis Nicola one month after the British Army evacuated the city. The plan, in great detail, outlines all twelve redoubts, the abatis, stockades, and a cremaillered work. Today no trace of them remains.

[1] G. D. Scull, “Journal of Captain John Montresor, July 1, 1777 to July 1, 1778, Chief Engineer of the British Army,” The Pennsylvania Magazine of History and Biography, 6 (1882), 42-43, hereinafter cited as Montresor.

[2] Ibid., 43.

[3] Ibid.

[4] Ibid., 44

[5] Ibid.

[6] Bruce E. Burgoyne transl. and edit., Johann Conrad Dohla, A Hessian Diary of the American Revolution, (Norman, OK: University of Oklahoma Press, 1990), 68-69.

[7] Montresor, 50.

[8] Ibid.

[9] Ibid., 51.

[10] Ernest Kipping, transl., and Samuel Stelle, annot., The Diary of General William

Howe’s aide de camp Captain Friedrich von Muenchhausen (Monmouth Beach, NJ: Philip Freneau Press, 1974), 40, hereinafter cited as Muenchausen.

[11] Johann Ewald, Diary of the American War, Joseph Tustin, ed., (New Haven, CT: Yale University Press, 1979), 96; Harry Miller, ed., Archibald Robertson, Lieutenant-General Royal Engineers, His Diaries and Sketches in America, 1762-1780,

(New York: The New York Public Library, 1930), 153; John Graves Simcoe, A Journal of the Operations of the Queen’s Rangers (New York: Bartlett & Welford, 1844; reprinted New York: The New York Times & Arno Press, 1968), 17; John Andre, Major Andre’s Journal, Operations of the British Army, June 1777 to November 1778 (Tarrytown, NY: William Abbatt, 1930; reprinted New York: The New York Times & Arno Press, 1968), 59.

[12] Montresor, 51.

[13] Ibid., 52.

[14] Ibid.

[15] Ibid., 53.

[16] Ibid.

[17] Ibid. 54.

[18] “Journal of Major Francois Louis Teissedre de Fleury, dated 27-30 October 1777,” in George Washington Papers, Series 4 (Library of Congress).

[19] Montresor, 54.

[20] Ibid., 56.

[21] Ibid.

[22] Ibid., 57.

[23] Ibid.

[24] Andre, Major Andre’s Journal, 64.

[25] Muenchhausen, 44.

[26] “Letter from Richard Platt to General John Lamb, in British Defences of Philadelphia,” John F. Watson, Annals of Philadelphia (Phildelphia: Stoddart & Co.,1881), 610.

[27] “To George Washington from Major John Clark, Jr., 17 November 1777,” The Papers of George Washington, Revolutionary War Series, Frank E. Grizzard, Jr. and David R. Hoth, ed. (Charlottesville: University of Virginia Press, 2002), 12:285-86.

[28] “Return of the Number and Nature of Ordnance in the severall Redoubts,” Collection: Montresor Family Archives on microfilm (1993), Harold Finigan.

[29] Bernard A. Uhlendorf & Edna Vosper, eds. “Letters of Major Baurmeister,” The Pennsylvania Magazine of History and Biography, 60 (1936), 44.

[30] Andre, Major Andre’s Journal, 71.

[31] Ibid., 195.

[32] Bernard A. Uhlendorf, trans, annot., Confidential Letters and Journals 1776-1784 of Adjutant General Major Baurmeister of the Hessian Forces, (New Brunswick, NJ: Rutgers University Press, 1957), 148; “To George Washington from Major John Clark, Jr., 23 December 1777,” The Papers of George Washington, 12:680-81.

[33] Andre, Major Andre’s Journal, 73.

[34] Uhlendorf & Vosper, eds. “Letters of Major Baurmeister,” 49-50.

[35] – molndal

[36] Montresor, 197.

[37] Ibid, 201.

[38] Ibid.

[39] Muenchhausen, 51.

[40] Montresor, 286.

[41] Ibid., 288.

[42] Ibid., 292.


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  • Bob,

    Many thanks for an interesting and informative article. I have been studying His Majesty’s Corps of Engineers in America during the Revolution for some time. My focus has been principally on the broader themes of who was where, when and what they were doing. Consequently I have not dug as deeply into the details of specific campaigns and actions as you have done here. You have given me new insights into not only the who, what, where and when of the engineers, but also the how and why of their work.

    • You might want to check out the Montresor papers. James (the father) and son John were, in their turn, the Chief Engineers for the British Army in N. America.

      They were responsible for building/sieging a great many forts.

      You can contact me at if you so desire.

  • Some years ago, I spent many months microfilming and cataloguing the papers of James & John Montresor that were in the family’s collection. I understand that the collection were subsequently broken up at auction. Alot of the information, drawings, notes, etc. to my knowledge have not been published.

    You can find copies of the microfilms at:

    1) The David Library of the American Revolution
    2) West Point Library, Fortifications Collection
    3) Royal Engineers Library, Chatham, Kent, UK

    Sadly, the staff at Fort Mifflin – Philadelphhia threw away the microfilm collection during a “moderinization” some years back

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