Born on January 17, 1726, at the manse of Pitsligo Kirk in Roseharty, Scotland, Hugh Mercer was the son of Reverend William Mercer and his wife Ann. At the age of 15, he left home to attend Marischal College at the University of Aberdeen to study medicine. Graduating as a doctor, he practiced locally until the arrival of Prince Charles Edward Stuart and the beginning of the 1745 Jacobite Rebellion. Rallying to the Prince's colors, Mercer became an assistant surgeon in the Jacobite Army. He remained in this service until the Prince was defeated by the Duke of Cumberland at the Battle of Culloden on April 16, 1746.
Escape to America:
Branded a rebel in the wake of Culloden, Mercer was forced to flee Scotland for America in 1747. Arriving in Philadelphia, he settled on the Pennsylvania frontier and returned to practicing medicine. After eight years of peace, Mercer was drawn back into the military after aiding the survivors of General Edward Braddock's disastrous campaign against Fort Duquesne. The following year, Mercer was commissioned as a captain in a Pennsylvania regiment and marched off to war. Battling Shawnee and Delaware Indians, Mercer and his men took part in Lt. Colonel John Armstrong's raid on Kittanning on September 8, 1756.
Though the raid was successful, Mercer was badly wounded in his right arm and became separated from his men. Alone following the battle, he made his way 100 miles on foot back to Fort Shirley where he received medical attention. Heralded as a hero, he was given a silver medal by the City of Philadelphia for his part in the raid. Over the next four years, Mercer steadily rose through the ranks, finishing the French & Indian War as a colonel. During this time, he befriended many of the officers from the Virginia regiments, including George Washington.
Move to Fredericksburg:
In 1760, Mercer followed his new friends back to Virginia where he took up residence in Fredericksburg. Possessing a vibrant and friendly Scottish community, Mercer was quickly at home and again returned to practicing medicine. Becoming a prominent businessman, Mercer counted many of the town's elite among his patients, including Washington's mother, Mary. While in Fredericksburg, Mercer married Isabella Gordon, the daughter of a local tavern owner. The couple would have five children, one of which married into the Patton family. This line would ultimately produce World War II hero General George S. Patton.
The American Revolution Begins:
With relations between Britain and the colonies deteriorating, Mercer was appointed to Fredericksburg's Committee of Safety in 1775. That August, he was excluded from the leadership of the new Virginia regiments being raised as he was considered a "northern Briton." This initial ban did not prevent him however, from being elected the colonel of the Minute Men of Spotsylvania, King George, Stafford, and Caroline Counties. That November he was named to the Committee of Safety of Spotsylvania County. On January 11, 1776, his ban was lifted and he was appointed colonel of the 3rd Virginia Regiment.
Marching with Washington:
As the 3rd Virginia marched north to join Washington's army, Mercer's officers included future president James Monroe and future Chief Justice John Marshall. In June 1776, Mercer was promoted to brigadier general by the Continental Congress and was ordered to oversee the construction of Fort Lee on the New Jersey side of the Hudson River. Abandoned on November 20, after the American defeats around New York, Mercer and his brigade retreated across New Jersey with the remnants of Washington's army. Crossing the Delaware River in early December, the army halted to regroup.
Lacking supplies and with enlistments expiring, the army began to melt away. Reduced to around 3,000 effectives, the army was at the end of its rope and action was needed. Morale improved later in the month with the publication Thomas Paine's The American Crisis and the arrival of 3,500 reinforcements. Looking to further boost morale, Washington began contemplating an offensive against the isolated British outposts in New Jersey. The plan that resulted called for an assault across the Delaware against the Hessian garrison at Trenton. Some sources suggest that it was Mercer who first suggested the plan.
Trenton & Princeton:
Crossing the icy Delaware on Christmas Night, Washington's army succeeded in defeating the Hessians and capturing Trenton. With the men encouraged by the victory, enlistments began to increase. After crossing back into Pennsylvania, it was decided to defend Trenton from the anticipated British counterattack. Moving back over the river, the army took up a position south of the town on high ground overlooking Assunpink Creek. On January 2, 1777, they were attacked by British forces led by Lt. General Charles Cornwallis. This assault was repulsed with heavy casualties and with Mercer's brigade playing a key role.
That night, Washington's army slipped away from Trenton with the goal of striking at Cornwallis' rear and capturing Princeton. On January 3, with his brigade leading one wing of the army's advance, Mercer was the first to encounter British resistance. Forming his men for battle in an orchard outside Princeton, Mercer's 1,200 men were attacked by 800 British under Lt. Colonel Charles Mawhood. Charging at the Americans, Mawhood's men were able to drive them from the orchard. In the fighting, Mercer's horse was shot from under him and he became isolated from his men.
Quickly surrounded by the British, who mistook him for Washington, he was ordered to surrender. Refusing to do so, he drew his sword and charged at the British troops. In the resulting melee, he was severely beaten with musket butts and run through with bayonets. Leaving him for dead, the British continued the battle. Seeing Mercer's men falling back, Washington brought reinforcements to the scene and was able to drive the British from Princeton. Found after the battle, Mercer was taken to the Thomas Clarke House for treatment. Though attended to by the famed patriot Dr. Benjamin Rush, his condition did not improve and he died nine days later on January 12, 1777.
His body was transported to Philadelphia where it was interred in the Christ Church Burial Ground. Later that year, one of the key forts on the Delaware River was named in his honor. It was successfully defended during the Battle of Red Bank (October 22, 1777), but was abandoned the following month after the fall of Fort Mifflin across the river. In 1840, his body was moved to the Laurel Hill Cemetery, overlooking the Schuylkill River, and placed under new memorial.