Hugh Mercer, born in Aberdeen, Scotland, in 1720, entered the army of Prince Charles Edward as assistant-surgeon, in 1745. The battle of Culloden, April 16, 1746, resulted in the total defeat of that unfortunate prince, sending him into exile, a proscribed wanderer, and scattering or exterminating his devoted followers. Emigrating to this country the following year, Mercer settled in Franklin County, Pennsylvania, and in 1755 fought his first battle in America under the leadership of John Armstrong and with the rank of captain. At the battle of Kittanning in 1756, he was severely wounded; in 1758, as lieutenant-colonel he took part in the capture of Fort Duquesne, and was left in command of that important post. It was during this expedition that he became acquainted with Washington; and in 1775, a few days after the battle of Lexington, Mercer was among the first to appeal to his former comrade-in-arms for instructions as to the disposition of the Virginia troops, then arming in the cause of liberty. June 5, 1776, Congress appointed him a brigadier-general; and a few days later he joined the army at New York and entered the Continental service, under the immediate orders of the commander-in-chief. Gloomy forebodings filled the mind of even the stanchest patriots, as defeat followed defeat, and Washington with his brave band retreated through the Jerseys.

In December, at a council of war, a change of policy was agreed upon, and the unexpected and successful attack upon Trenton was the result, Mercer rendering most efficient service. The British, however, gathering their forces, made ready to retaliate; and the cause of liberty seemed lost, when Mercer boldly suggested by a night march to surprise them in their stronghold at Princeton. His advice was acted upon; but in that memorable battle—a battle that did more to secure us our independence than any other during the war—the brave General Mercer lost his life. Dismounted by the death of his horse, and separated from his command, disdaining to surrender, he met single-handed a detachment of the enemy, and was beaten to the earth by the butts of their muskets and stabbed by their bayonets. Carried by his aid from the battle-field to a neighboring house, he lingered for nine days in great agony, expiring on the 12th of January, 1777. His remains were taken to Philadelphia, where his funeral was attended by thirty thousand people. St. Andrew’s Society of that city have erected a monument to his memory at Laurel Hill Cemetery. Mercer County, Kentucky, was named in his honor.