Fort Duquesne was a fort established by the French in 1754, at the junction of the Allegheny and Monongahela rivers in what is now downtown Pittsburgh in the U.S. state of Pennsylvania.

The point where the Allegheny and Monongahela rivers merged to form the Ohio River was long seen as important for controlling the Ohio Country, both for settlement and for trade. Englishman William Trent had established a highly successful trading post at the forks as early as the 1740s. Both the French and the British were keen to gain advantage in the area. In the early 1750s, the French commenced construction of a series of forts, starting with Fort Presque Isle on Lake Erie near present-day Erie, Pennsylvania, followed by Fort Le Boeuf , about twenty miles inland near present-day Waterford, and Fort Marchault , on the Allegheny River in Venango County in present-day Franklin. Lieutenant Governor of the Virginia Colony, Robert Dinwiddie, saw this as threatening to the extensive claims to land in the area by Virginians (including himself).

In late autumn 1753, Dinwiddie dispatched a young George Washington to the area, both to conduct surveys and to present a challenge to the French presence. Washington reached Fort Le Boeuf in December and was politely rebuffed by the French. Following Washington's return to Virginia in January 1754, he sent Virginians to build Fort Prince George at the forks. Work began on the fort on February 17 and Washington, who had been promoted to Lt. Colonel, left on April 2 as part of a small force with the dual purpose of constructing a road and defending the fort upon their arrival. By April 18, a much larger larger French force had forced the English to abandon work on the fort, which was then completed by the French and named it Fort Duquesne in honor of Marquis Duquesne, the governor-general of New France. Washington was at Wills Creek in south central Pennsylvania when he received news of the surrender of Fort Prince George.

On May 25, Washington assumed command of the expedition upon the death of Colonel Fry. Two days later, Washington encounters a French scouting party near a place known as Great Meadows (several miles southeast of present-day Uniontown). Washington attacks the French, some of whom escape, and then orders construction of Fort Necessity in that location. On July 3, the French forced Washington to surrender Fort Necessity but allowed Washington and his men to return without their armaments.

The French held Fort Duquesne during the French and Indian War, and it became one of the focal points for that war because of its location in disputed territory. The French held the fort successfully early in the war, turning back the Braddock Expedition led by General Edward Braddock. Three years later on November 25, 1758, the Forbes Expedition under General John Forbes captured the site after the French destroyed Fort Duquesne the day before. The British rebuilt the fort and renamed it Fort Pitt.

The Fort was located where the Allegheny and Monongahela rivers meet to form the Ohio, at the part of downtown Pittsburgh now known as Point State Park or "the Point".