Fort Duquesne (/djuː.ˈkeɪn/ dew-KAYN, French: [dykɛːn]; 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 as Pittsburgh in the U.S. state of Pennsylvania. Fort Duquesne was destroyed by the French before its British conquest during the Seven Years' War, known as the French and Indian War on the North American front. The British replaced it, building Fort Pitt between 1759 and 1761. The site of both forts is now occupied by Point State Park, where the outlines of the two forts have been laid in granite slabs.

Fort Duquesne, built at the confluence of the Allegheny and Monongahela rivers which form the Ohio River, was considered strategically important for controlling the Ohio Country, both for settlement and for trade. The English merchant William Trent had established a highly successful trading post at the forks as early as the 1740s, to do business with a number of nearby Native American villages. Both the French and the British were keen to gain advantage in the area.

As the area was within the drainage basin of the Mississippi River, the French had claimed it as theirs. They controlled New France (Quebec), the Illinois Country along the Mississippi, and La Louisiane, the ports of New Orleans and Mobile, Alabama.

In the early 1750s, the French began construction of a line of forts, starting with Fort Presque Isle on Lake Erie in present-day Erie, Pennsylvania, followed by Fort Le Boeuf, about 15 miles south in present-day Waterford, Pennsylvania, and Fort Machault, on the Allegheny River in Venango County in present-day Franklin, Pennsylvania.

Robert Dinwiddie, Lieutenant Governor of the Virginia Colony, thought these forts threatened extensive claims to the land area by Virginians (including himself) of the Ohio Company.

In late autumn 1753, Dinwiddie dispatched a young Virginia militia officer named George Washington to the area to deliver a letter to the French commander at Fort Le Boeuf, asking them to leave. Washington was also to assess French strength and intentions. After reaching Fort Le Boeuf in December, Washington was politely rebuffed by the French.

Following Washington's return to Mount Vernon in January 1754, Dinwiddie sent Virginians to build Fort Prince George at the Forks of the Ohio. Work began on the fort on February 17. By April 18, a much larger French force of five hundred under the command of Claude-Pierre Pécaudy de Contrecœur arrived at the forks, forcing the small British garrison to surrender. The French knocked down the tiny British fort and built Fort Duquesne, named in honor of Marquis Duquesne, the governor-general of New France. The fort was built on the same model as the French Fort Frontenac on Lake Ontario.

Washington, who was lieutenant colonel in the newly created Virginia Regiment, set out on April 2, 1754, with a small force to build a road to, and then defend, Fort Prince George. Washington was at Wills Creek in north central Maryland when he received news of the fort's surrender. On May 28, Washington encountered a Canadian scouting party near a place now known as Jumonville Glen (several miles east of present-day Uniontown). Washington attacked the French Canadians, killing 10 in the early morning hours, and took 21 prisoners, of whom many were ritually killed by the Native American allies of the British. On May 31, Washington replaced Colonel Joshua Fry as commander of the Virginia Regiment after Colonel Fry died en route to Wills Creek.