Mercer's Fort was a temporary fort built by Colonel

Hugh Mercer Hugh Mercer (January 16, 1726 – January 12, 1777) was a Scottish brigadier general in the Continental Army during the American Revolutionary War. He fought in the New York and New Jersey campaign and was mortally wounded at the Battle of Pri ...

during the winter of 1758–1759, to secure the "forks of the Ohio," at the confluence of the

Monongahela River The Monongahela River ( , ), sometimes referred to locally as the Mon (), is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 river on the Allegheny Plateau in nor ...

and the

Allegheny River The Allegheny River ( ; ; ) is a tributary of the Ohio River that is located in western Pennsylvania and New York (state), New York in the United States. It runs from its headwaters just below the middle of Pennsylvania's northern border, nor ...

, where Mercer was preparing to build Fort Pitt.Brady J. Crytzer, ''Fort Pitt: A Frontier History,'' Arcadia Publishing, 2014
/ref> At the time it was loosely known as "the fort at Pittsburgh," and when work on Fort Pitt had progressed, it was sometimes referred to as "the first Fort Pitt." Only later did people call it "Mercer's Fort," leading to confusion with

Fort Mercer Fort Mercer was an earthen fort on the eastern shores of the Delaware River in New Jersey that was constructed by the Continental Army during the American Revolutionary War. The fort was built in 1777 by Polish engineer Thaddeus Kosciuszko und ...

in New Jersey. The fort initially served to defend the site, but as Fort Pitt neared completion, it was used mostly to lodge workers and to store supplies. In mid-1760 it was partially dismantled, with some buildings converted into a hospital.

Background

In January 1754 Major George Washington, returning from a meeting with the French commander at

Fort Le Boeuf Fort Le Bœuf (often referred to as Fort de la Rivière au Bœuf) was a fort established by the French during 1753 on a fork of French Creek (in the drainage area of the River Ohio), in present-day Waterford, in northwest Pennsylvania. The fort ...

, observed the land at the confluence of the

and the

Ohio River The Ohio River () is a river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing in a southwesterly direction from Pittsburgh, Pennsylvania, to its river mouth, mouth on the Mississippi Riv ...

, and felt it would be an ideal location for a fort, which would then serve to monitor river traffic heading west into the

Ohio Country The Ohio Country (Ohio Territory, Ohio Valley) was a name used for a loosely defined region of colonial North America west of the Appalachian Mountains and south of Lake Erie. Control of the territory and the region's fur trade was disputed i ...

. As the French had already started building a chain of forts south of

Lake Erie Lake Erie ( ) is the fourth-largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and also has the shortest avera ...

, it seemed likely that they would build a fort at this spot, therefore Governor James Hamilton attempted to get funding from the

Pennsylvania Provincial Council The Pennsylvania Provincial Council helped govern the Province of Pennsylvania from 1682 to 1776. The provincial council was based on the English parliamentary system and was analogous to the Upper House or House of Lords. From the Frame of Govern ...

for an English fort, without success.Samuel Hazard, ed. ''Minutes of the Provincial Council of Pennsylvania: From the Organization to the Termination of the Proprietary Government, Mar. 10, 1683-Sept. 27, 1775,'' Vol 4 of Colonial Records of Pennsylvania, Pennsylvania Provincial Council, Pennsylvania Committee of Safety; J. Severns, 1851.
/ref> The

Ohio Company The Ohio Company, formally known as the Ohio Company of Virginia, was a land speculation company organized for the settlement by Virginians of the Ohio Country (approximately the present U.S. state of Ohio) and to trade with the Native Ameri ...

of Virginia was willing to fund the fort's construction, however, and in February Virginia Governor Robert Dinwiddie sent

William Trent William Trent (February 13, 1715 – 1787) was an American fur trader and merchant based in the colonial-era Province of Pennsylvania. He was commissioned as a captain of the Virginia Regiment in the early stages of the French and Indian War, wh ...

and a small number of Virginia militia to start construction of what was later named

Fort Prince George Fort Prince George (sometimes referred to as Trent's Fort) was an incomplete fort on what is now the site of Pittsburgh, at the confluence of the Allegheny and Monongahela Rivers in Allegheny County, Pennsylvania. The plan to occupy the strategi ...

. By April, the land had been cleared and a storehouse built, but the French discovered the project and sent a large force of infantry and artillery to capture it.Cherry, Jason A. ''Pittsburgh's Lost Outpost: Captain Trent's Fort.'' Charleston, SC: HISTORY Press, 2019.
/ref> They built

Fort Duquesne Fort Duquesne ( , ; originally called ''Fort Du Quesne'') was a fort established by the French in 1754, at the confluence of the Allegheny and Monongahela rivers. It was later taken over by the British, and later the Americans, and developed ...

at the same site, and maintained control over Ohio River traffic until the

Forbes Expedition The Forbes Expedition was a British military campaign to capture Fort Duquesne, led by Brigadier-General John Forbes in 1758, during the French and Indian War. While advancing to the fort, the expedition built the Forbes Road. The Treaty of Eas ...

threatened to take the fort. On November 24, 1758, the French burned Fort Duquesne and retreated. Within two weeks, Colonel Hugh Mercer had started construction on a temporary fort, to serve as lodging, storage and defense during the building of the much larger Fort Pitt.

Construction

The temporary fortification was built just south of what later became the Flag Bastion, now located in

Point State Park Point State Park (locally known as The Point) is a Pennsylvania state park which is located on in Downtown Pittsburgh, Allegheny County, Pennsylvania, US, at the confluence of the Allegheny and Monongahela rivers, forming the Ohio River. B ...

. It was located on the north bank of the Monongahela at the south end of what, later, was West street in the city of

Pittsburgh Pittsburgh ( ) is a city in Allegheny County, Pennsylvania, United States, and its county seat. It is the List of municipalities in Pennsylvania#Municipalities, second-most populous city in Pennsylvania (after Philadelphia) and the List of Un ...

, and between West street and Liberty Avenue, about 200 yards east of the ruins of

. It was a small stockade with

bastion A bastion is a structure projecting outward from the curtain wall of a fortification, most commonly angular in shape and positioned at the corners of the fort. The fully developed bastion consists of two faces and two flanks, with fire from the ...

s, designed to accommodate a garrison of 200 men, built between December 1758 and early January 1759. It was intended only for temporary use, to defend against French or Native American attacks while the main fort was under construction. Colonel Hugh Mercer was placed in command, and the rest of the army marched back to the settlements. Mercer's Fort was a square stockade with the walls formed by the backs of the interior buildings. Mercer chose not to build an outer wall, but instead constructed three barracks, the commandant's house, and a storeroom facing the gate, with four diamond-shaped bastions between them, at each corner.Stotz, Charles Morse. ''Drums in the Forest: Decision at the Forks, Defense in the Wilderness.'' University of Pittsburgh Pre, 2005.
/ref> Smaller separate houses for the officers and the bombardiers were located in the northern bastions. The southern bastions held the

gunpowder magazine A gunpowder magazine is a magazine (building) designed to store the explosive gunpowder in wooden barrels for safety. Gunpowder, until superseded, was a universal explosive used in the military and for civil engineering: both applications re ...

and the hospital. The fort was purposely built on the Monongahela riverbank, so that the troops could escape by boat downriver in the event of an overwhelming assault. Outside the fort Mercer had a "council house" built, for meetings with Native Americans, as he knew that maintaining good diplomatic relations with them was a key part of the fort's defense. This was the venue for a number of important conferences, the first of which took place on July 4, 1759, and included

George Croghan George Croghan (c. 1718 – August 31, 1782) was an Kingdom of Ireland, Irish-born fur trader in the Ohio Country of North America (current United States) who became a key early figure in the region. In 1746 he was appointed to the Onondaga Cou ...

, Colonel Mercer,

Andrew Montour Andrew Montour ( – 1772), also known as Sattelihu, Eghnisara,Hagedorn, 57 and Henry,Montour was also called Henry, possibly due to the similarity of sound with the French ''"Andre".'' was an important mixed interpreter and negotiator in th ...

, interpreter, Lenape chief King Beaver, and Seneca war leader

Guyasuta Guyasuta (c. 1725–c. 1794; , "he stands up to the cross" or "he sets up the cross") was an important Native American leader of the Seneca (tribe), Seneca people in the second half of the eighteenth century, playing a central role in the di ...

. Due to the severe cold, construction was painfully slow, as the frozen soil was difficult to dig and felled trees had to be dragged across the icebound river. On December 19, Mercer wrote to his commander, Colonel Henry Bouquet: "I expect in four Days to have the Place made capable of a tolerable Defence, and am fully determined to maintain the Post, or at least, make it as dear a Purchase to the Enemy as possible." Engineer Harry Gordon was sent to advise Mercer on construction. On January 3, Mercer wrote to Bouquet that "Nine Hundred and Fifty men may be contained in the Fort by building Barracks opposite the storehouses, and hutts might be raised in the front within the Intrenchments you have Directed to be made, to lodge 100 more." On January 19 Mercer wrote, "I am glad to have Mr. Gordon's Directions and shall conform to them...Another Row of Barracks are now raising, opposite the Stores." An additional row of barracks was built along the shore, to house the hundreds of men needed to construct the massive Fort Pitt. In April 1759, General Henry Bouquet asked Mercer to relocate the fort to higher ground, and sent another British engineer James Robertson to assist him. The engineer recommended a hilltop in what is now

Chartiers Township, Pennsylvania Chartiers Township is a township in Washington County, Pennsylvania, United States. The population was 8,628 at the 2020 census. Along with the borough of Houston, the township makes up the Chartiers-Houston School District. It is part of th ...

, which Mercer agreed was "strong, convenient, heathfull, and pleasant," but noted that they would need long chains "for drawing up water, wood, etc. either by Cranes or

Windlass The windlass is an apparatus for moving heavy weights. Typically, a windlass consists of a horizontal cylinder (barrel), which is rotated by the turn of a crank or belt. A winch is affixed to one or both ends, and a cable or rope is wound arou ...

es."

Garrison

On January 8, 1759, Colonel Mercer reported to Governor William Denny that he had a garrison of about 280 men, and that the "works" were capable of some defense. On March 17, 1759, the garrison totaled 428 men: 10 commissioned officers, 18 non-commissioned officers, 3 drummers, 346 rank and file, fit for duty, 79 sick, and three unaccounted for. Twelve had died since 1 January. Separate units included:

Royal Artillery The Royal Regiment of Artillery, commonly referred to as the Royal Artillery (RA) and colloquially known as "The Gunners", is one of two regiments that make up the artillery arm of the British Army. The Royal Regiment of Artillery comprises t ...

, 8;

Royal Americans The King's Royal Rifle Corps was an infantry rifle regiment of the British Army that was originally raised in British North America as the Royal American Regiment during the phase of the Seven Years' War in North America known in the United Sta ...

, 20; Highlanders, 80;

Virginia Regiment The Virginia Regiment was an infantry unit of the Virginia Provincial Forces raised in 1754 by the Virginia General Assembly and Governor Robert Dinwiddie for service in the French and Indian War. The sole provincial unit raised by the British ...

, 99; First Pennsylvania Battalion, 136; Second Pennsylvania Battalion, 85.Clarence M. Busch, ''Report of the Commission to Locate the Site of the Frontier Forts of Pennsylvania,'' Vol. 1, State Printer of Pennsylvania, 1896
/ref> By December 1759, the garrison consisted of 300 Pennsylvania and Virginia militia and 400 Pennsylvania infantry, plus 21 officers.

Military history

On March 25 1759, Colonel Mercer launched an assault on

Fort Machault Fort Machault (, ) was a fort built by the French in 1754 near the confluence of French Creek with the Allegheny River, in northwest Pennsylvania. (Present-day Franklin developed here later.) The fort helped the French control these waterways, ...

, the nearest French fort, which the French had been strengthening. Two hundred men marched on land while fifty men escorted ten

bateaux A bateau or batteau is a shallow-draft, flat-bottomed boat which was used extensively across North America, especially in the colonial period and in the fur trade. It was traditionally pointed at both ends but came in a wide variety of sizes. T ...

of supplies on the river. The troops were slowed by heavy rains and a river swollen with snowmelt, however, and by March 28 they had advanced only twenty miles when Shawnee and

Lenape The Lenape (, , ; ), also called the Lenni Lenape and Delaware people, are an Indigenous peoples of the Northeastern Woodlands, Indigenous people of the Northeastern Woodlands, who live in the United States and Canada. The Lenape's historica ...

warriors attacked them, killing the men in one boat and causing the other men on the river to turn back. The troops on land also retreated, and the assault was abandoned.Hunter, William Albert. ''Forts on the Pennsylvania Frontier: 1753–1758,'' (Classic Reprint). Fb&c Limited, 2018
/ref> Mercer's Fort was never attacked, but in June 1759 Colonel Mercer learned that a French force of 700 troops, 800 Native American warriors, and some artillery was advancing from

, intending to attack Mercer's Fort and

Fort Ligonier Fort Ligonier is a British fortification from the French and Indian War located in Ligonier, Pennsylvania, United States. The fort served as a staging area for the Forbes Expedition of 1758. During the eight years of its existence as a garrison, ...

. The French were only a day's march from Pittsburgh when the attack was aborted, as the French forces were diverted when British troops arrived to attack

Fort Niagara Fort Niagara, also known as Old Fort Niagara, is a fortification originally built by New France to protect its interests in North America, specifically control of access between the Niagara River and Lake Ontario, the easternmost of the Great L ...

, in what would become the

Battle of Fort Niagara The Battle of Fort Niagara was a siege late in the French and Indian War, the North American theatre of the Seven Years' War. The British siege of Fort Niagara in July 1759 was part of a campaign to remove French control of the Great Lakes and ...

Dismantling, 1760

As fighting diminished towards the end of the

French and Indian War The French and Indian War, 1754 to 1763, was a colonial conflict in North America between Kingdom of Great Britain, Great Britain and Kingdom of France, France, along with their respective Native Americans in the United States, Native American ...

, Mercer's Fort was used less for defense and more as housing for workers and to store supplies until mid-1760, when work on Fort Pitt had progressed to the point where the older fort was no longer necessary. It was dismantled, with the wood recycled for use in other construction.History of Fort Pitt (1759-1797)
/ref> In October 1762, Indian trader James Kenny noted the changes as the older outbuildings were razed or converted: "Where two years ago I had seen all ye Houses that were without ye Little Fort they had then, thrown down, only one he Indian conference housewhich stands yet, also two that was within that little fort...being ye Hospital now."John W. Jordan, ed., "Journal of James Kenny, 1761–1763," ''Pennsylvania Magazine of History and Biography,'' 37 (1913)
/ref>

References

External links

Artist's rendition of Mercer's Fort soon after its completion, p. 15. Stuart P. Boehmig, ''Downtown Pittsburgh: Images of America,'' Images of America: a history of American life in images and texts, Arcadia Publishing, 2007
{{rp, 15 French and Indian War forts Forts in Pennsylvania Colonial forts in Pennsylvania British forts in the United States Fort Pitt (Pennsylvania) Allegheny County, Pennsylvania Buildings and structures in Allegheny County, Pennsylvania Pre-statehood history of Pennsylvania