A Visit to Old Fort Mercer on the Delaware


August 9, 2018
by Rand Mirante Also by this Author


Journal of the American Revolution is the leading source of knowledge about the American Revolution and Founding Era. We feature smart, groundbreaking research and well-written narratives from expert writers. Our work has been featured by the New York Times, TIME magazine, History Channel, Discovery Channel, Smithsonian, Mental Floss, NPR, and more. Journal of the American Revolution also produces annual hardcover volumes, a branded book series, and the podcast, Dispatches

A motorist travelling northbound through New Jersey along Interstate 295, which tracks the east bank of the Delaware River from the Delaware Memorial Bridge, passes opposite Philadelphia, and ends a short ways beyond Trenton, might think he or she is in Europe, based strictly on fleetingly observed exit signs rather than any resemblances evoked by the surrounding flatlands. Turn-off markers for towns such as Florence, Mantua, Berlin, Swedesboro, and even Runnemede flash by, creating an allusive and elusive sense of déjà vu. The most attention-getting sign, however, for this readership at least, does have a truly European connection. It’s the one for “Hessian Avenue,” and it commemorates the approximate approach-route traversed in 1777 by Col. Carl von Donop and his 1200 seasoned professionals drawn from three grenadier battalions, a fusilier regiment, and the corps of Jägers. They were headed towards their fatal and futile assault on the determined defenders of Fort Mercer, a critical link in the riverine defensive network that threatened to choke off the British high command’s ability to adequately supply its troops and the residents of occupied Philadelphia.

Hessian Avenue, National Park, New Jersey. (Author)

Turning down Hessian Avenue—which is likely one of only a handful of streets in the United States named for a foreign enemy of the Republic—you drive for about two miles westward, past one-story bungalows, Cape Cods, and a V.F.W. meeting hall, until arriving at the gate to the Red Bank Battlefield Park, administered by Gloucester County. On the left, in front of an amusement and picnic area, is a long red shed with a viewing window (more on that later); straight ahead is the red-brick James and Ann Whitall house, dating from 1748 and the home of the unfortunate and unwilling Quaker hosts to what was surely one of the more astounding battles of the Revolution; and to the right are the outlines and vestiges of the works of Old Fort Mercer. There is a scenic and commanding view of the Delaware from a set of eroded bluffs, which the Whitall house and the fort overlook. The latter’s strategic value is immediately apparent. About a half-mile directly across the river is Fort Mercer’s sister link, Fort Mifflin, situated on what was once an island and now subsumed into the same land-mass as Philadelphia International Airport. The city of Philadelphia is easily viewed through a tree line on the bluffs adjacent to the northern boundary of Fort Mercer’s perimeter.

The James and Ann Whitall House, National Register of Historic Places. (Author)

In the fall of 1777, Mercer and Mifflin were the twin bastions which, supplemented by the gun-boat galleys of the Pennsylvania Navy, sunken chevaux-de-frise, booms and chains, fire ships, and the natural obstacles posed by shoals and shifting sand bars, created the cordon which blocked Adm. Sir Richard Howe from convoying supplies upriver to his brother’s army of occupation in the former capital of the United States (see map at top). It was infeasible to bring adequate provisions overland to supply Gen. Sir William Howe’s force of 15,000 soldiers plus the resident civilians, and by October the British army was on half-rations.[1] Thus commenced the dramatic British effort to achieve breakthrough via the bombardment of Fort Mifflin by shore batteries on the Pennsylvania side and by the Royal Navy, and to eliminate the covering fire Mercer provided to Mifflin by means of a Hessian crossing of the Delaware. That crossing would be less famous (and the ultimate results disastrous) when juxtaposed with the ones carried out by the Americans at the end of the preceding year.

The fort that von Donop’s Hessians assaulted on October 22 consisted of unfinished but nevertheless formidable earthworks, with some portions possibly layered with timbers. It was surrounded by trenches with sharpened abatis—fabricated from the orchards of the unhappy Whitalls—scattered throughout, which were intended to break up any attacking formation. Today, only the outlines of Fort Mercer’s earthworks and the trenches remain. Those vestiges are roughly in the shapes of a pentagon and of a larger, acute trapezoid placed right next to each other; by contemplating those shapes, the visitor can readily appreciate the Americans’ winning strategy.[2] Simply put, the fort was too large to be defended by its small garrison of approximately 500 men, comprised of two Rhode Island regiments, some New Jersey militia, and Continental artillery. So Fort Mercer’s resolute commander, Col. Christopher Greene (a veteran of Arnold’s epic march on Quebec and a distant relative of Gen. Nathanael Greene), with the advice and direction of the French fortifications expert Thomas-Antoine, Chevalier de Mauduit du Plessis, placed his entire force within the pentagon and abandoned the trapezoid. (Greene’s statue stands atop a tall column which is planted squarely within the footprint of the fort, which can readily be seen from the Pennsylvania side of the river as one drives to or from the airport.)

The monument featuring Christopher Greene at Red Bank Battlefield Park. (Author)

The Hessians came on in two waves in the late afternoon. One assault wave, personally led by von Donop, attacked the pentagon/citadel from the east and was cut to pieces. The other wave, coming from the north, effortlessly rushed into the trapezoid, which thereupon became a killing field as a result of withering fire from inside the pentagon and also from shelling originating outside the fort, delivered by Pennsylvania Navy galleys hugging the east bank of the Delaware. Von Donop was grievously hit in both legs and captured. He died within several days, and he was initially buried right outside the Whitalls’ house.[3] A staggering one-third of his courageous command were killed, wounded, or taken prisoner. A marker at the fort apprises the visitor of words attributed to (or placed in the mouth of) the expiring von Donop:“It is finishing a noble career early; but I die the victim of my ambition, and of the avarice of my sovereign.”[4] American casualties were relatively light.

More substantial than the marker about the Hessian colonel is a low, long stone monument with several bas-reliefs commemorating the battle and Gen. Hugh Mercer, the fort’s namesake. The heroic Mercer had also died of his wounds, in his case suffered at the Battle of Princeton earlier in 1777. Mercer’s sculpted head is topped by a tam o’shanter, reflecting his Highland origins—he had once served as a surgeon’s mate in Charles Stuart’s Jacobite army at the Battle of Culloden—only to find death, like von Donop, far from his original homeland and on a Quaker farm in New Jersey.

Scattered around the fort are a number of cannons. One, set upon a concrete carriage and pointing towards the river, bears the royal coat of arms; there are also a couple of damaged ones, exhibiting blown breeches. They are said to be relics of the sixty-four-gun ship HMS Augusta, one of the most powerful ships of Adm. Howe’s Delaware River squadron.[5] Augusta ran aground in an attempt to support the Hessians’ assault; peppered by fierce American counter-fire from the land and the river galleys, its powder magazine ignited the next day, October 23, and it blew up spectacularly. The volcanic detonation resonated for many miles, and was audible well north of Philadelphia.[6] The guns with the blown breeches/barrels on display today had been salvaged by the Americans and, according to their present markers, exploded on being test-fired.

Cannon on display at the Fort Mercer site. (Author)

A guide at the park (who imaginatively used a spontoon instead of a pennant) mentioned to me during one of my visits that at the time of the celebration of the Centennial in 1876, the Augusta was raised with the intention of transporting her the very short distance upriver to Philadelphia to be put on exhibit. She sank once again whilst being towed and convoyed. Her remains were displayed (subject to charged admission) on a spit off Gloucester City, New Jersey; her bones were visible until the 1930s, and some of her remnants adorn a room in the Daughters of the American Revolution headquarters in Washington, DC, as paneling.[7]

A variety of artifacts are displayed at Fort Mercer, including these hot-shot tongs. (Author)

Now, back to the aforementioned red shed.  Somewhat jumbled together within, and without any apparent labeling, is an astonishing collection of military artifacts salvaged from the Delaware: grapeshot, housing boxes to secure the chevaux-de-frise obstacles, chains, sections of a log boom, hot-shot tongs, an anchor, and scores of projectiles. The visitor must peer through a window at this unilluminated assemblage, but there is something particularly evocative about viewing this mute evidence of the violence and desperation of the long-ago struggle for control of the river.

Fort Mercer eventually had to be abandoned, and Fort Mifflin, on the verge of complete obliteration by British ship and shore batteries, was abandoned as well.  By November 1777, the defenses of the Delaware had been reduced and removed. The river was open. Philadelphia was now securely in the hands of the Crown, at least for the coming winter months.

On a visit to the park in April 2018, I was initially quite impressed to see clusters of individuals walking the fort’s paved pathways while fixedly staring at their iPhones; my naïve assumption was that there was an app available that served to explain the historic site. However, the same knowledgeable guide I have just mentioned informed me, with an air of understandably disappointed bemusement, that these people were in fact avid players of Pokemon Go, intent upon searching for augmented-reality cartoon monsters in a setting where any modest meditation about the events of 241 years ago would certainly conjure up far more meaningful specters. O tempora, o mores.

Nevertheless, for the thoughtful visitor, a trip to Fort Mercer will provide a rich and reflective experience.  It is highly and enthusiastically recommended.[8]


[1]Alfred Hoyt Bill, New Jersey and the Revolutionary War (Princeton: Van Nostrand, 1964), 58.

[2]Fort Mercer was part of an original defensive system designed in 1776 by the famous Polish engineer and intrepid patriot Tadeusz Kosciuszko; he is commemorated at the Red Bank site by a plaque commissioned by the Copernicus Society of America.

[3]Von Donop’s grave marker is gone, and there is an apparently unverified claim that his skull is in the possession of Rutgers University. See historicplacessj.blogspot.com/2011/01/is-this-skull-of-count-carl-von-donop.html. Historian-traveler Benson Lossing reported in the late 1840s that he saw the marker (which he also sketched), describing it as a “small, rough sandstone, about fourteen inches in height.” Due to the depredations of vandals, Lossing was only able to make out this portion of an inscription: “DONOP WAS LOST.” Lossing added that the Hessian commander’s skull was in the possession of a “physician of New Jersey”—perhaps part of the chain leading to its present possessor? Benson J. Lossing, The Pictorial Field-Book of the Revolution (New York: Harper, 1859), 2: 84.

[4]Leonard Lundin, Cockpit of the Revolution (Princeton University Press, 1940), 352.

[5]It’s my guess that one or more of the artifacts on display at the park may be from HMS Merlin, an eighteen-gun sloop that also grounded near the fort at the same time as the Augusta.

[6]Thomas Paine reported in a letter to Benjamin Franklin that while he was between Germantown and Whitemarsh, well north of Philadelphia proper, “we were stunned with a report as loud as a peal of a hundred cannon at once . . . [we] saw a thick smoke rising like a pillar and spreading from the top like a tree” —the classic mushroom cloud. Quoted in John W. Jackson, With the British Army in Philadelphia 1777-1778 (San Rafael: Praesidio Press, 1979), 71.

[7]See the picture and description of the “New Jersey Room,” one of the DAR Museum’s “Period Rooms” shown on their website: www.dar.org/museum/dar-museum-period-rooms.

[8]For information about the Red Bank Battlefield Park: www.co.gloucester.nj.us/depts/p/parks/parkgolf/redbank/default.asp.



  • There are a number of comments on the guns exploded at Mercer:

    November 11, 1777, Fort Mercer
    “We burst an eighteen pounder which was got from the wreck of the agusta, and killed one Man & by the Scales & peaces of the Carrage Eighteen More where slightly wounded-“—Jeremiah Greenman, 84.

    “11th. The Bumbarding and Cannonading begun early this morning. at Nine o Clock this morning a Shocking Accident happened in our fort at Red Banks. our french Enginear burst one of our Guns, an Eighteen Pounder, and kill’d one Benjamin Ross belonging to Colo. Greens Regt. and wounded Ten more men. this Gun I beleave was Split through the ignorance of the Engenear.”—Israel Angell, Diary.

    “An 18 pounder the rebels weighed from the wreck of the Augusta, burst in firing it at our Batteries from Red Bank, killed 1 and wounded 8 in the N. E. stockade.”—Montresor, 475.

    “At Red Bank, an Eighteen Pounder burst-one man killed and several wounded….”—Varnum, Woodberry, 11th Novr 12 o’Clock P.M. 1777, to Washington, Defences of Philadelphia in 1777, ed. Worthington Chauncey Ford (1897; reprint, New York: Da Capo Press, 1897), 116.

    “Tusday the 11th the Enemy Began to Cannonade Fort Miffilin & Continued the whole Day & after a[lso] we fird several shot from fort Mercer at them & about 9 oClock we split an 18 pounder which was Teaken out of the wreck of the Augusta wh[ich] was burnt in this River the 23 of Octr Killd Benjn. Ross the bombardier & wounded the Boatswain [ ] Class & put out one of his Eyes & wounded one or two others slightly.”—John Smith Diary, American Antiquarian Society.
    N. B. Front part of exploded 18 pounder is on exhibit at the Gloucester County Historical Society.

    November 12, 1777
    “One man killed & wounded mortally [sic] and the officer of artillery slightly wounded by the unexpected bursting of one of our 8 inch shells. . . . One of our shells burst and killed 2 men on the Battery.”—Montresor, 475.

    November 14, 1777, Fort Mercer
    “we burst a 24 pounder this day that was got from the wreck of the agusta.”—Greenman, 85.

    “The french Engenear burst a 24 pounder in the fort at Red Banks this afternoon, improoving her, he had no more judgement then to put in 20 pounds of powder and two wads and two balls.”—Angell, Diary.

  • Thank you for this article Rand. I didn’t know about this site, I’m sorry to say, and I’m not too far in Flemington, NJ. I’m currently reading Washington’s Immortals by Patrick O’Donnell about the 1st Maryland Regiment, and there’s a section on Fort Mifflin (one of the most interesting I’ve read). If the rain backs off this weekend I may take a drive there.

  • Thank you for the article. I have just “discovered” the American Revolution and have had my head down reading and gathering as much information as possible. Just fascinating. All the missed opportunities I had in my early years when I lived in the Washington DC area. Too bad I now live in Ohio!

  • I read Mr. Mirante’s excellent post on Ft. Mercer with much interest. (I was the spontoon-wielding guide for his tour.) He captured both the importance and relative obscurity of our wonderful Park with real insight. He also well-identified many of the the rich and surprising rewards of a visit. (One other is that what is believed to be the third oldest surviving Revolutionary-War monument in the US-ca. 1829- still stands on the Battlefield !) I deeply appreciate his kind attention and appreciation for this marvelous, but overlooked site. We welcome visitors Thurs.-Sunday from 1-4 PM during the Summer and on Sundays 1-4PM until early December. The annual Battle-Reenactment/Field Day will be held on Oct. 21st 2018. Our annual Candlelight Christmas Tour will be Dec. 7-9th. Admission to the Park/Whitall House and events is free-courtesy the Gloucester County Board of Chosen Freeholders.

Leave a Reply

Your email address will not be published. Required fields are marked *