Fort Pitt was a fort in what is now the city of Pittsburgh, Allegheny County, Pennsylvania. The fort was built in 1758 during the French and Indian War, next to the site of Fort Duquesne. The French built Fort Duquesne in 1754, at the beginning of that war, and it became a focal point due to its strategic river location. The Braddock expedition, a 1755 attempt to take Fort Duquesne, met with a bloody repulse at the Monongahela River. The French garrison viciously mauled an attacking British regiment in September 1758, but abandoned and destroyed the fort at the approach of General John Forbes's expedition in November.

The Forbes expedition was successful where the Braddock expedition had failed because of the Treaty of Easton, in which area American Indians agreed to abandon their alliance with the French. American Indians—primarily Delawares and Shawnees—made this agreement with the understanding that the British military would leave the area after the war. The Indians wanted a trading post on the spot, but they did not want a British army garrison. The British, however, built a new fort on the site and named it Fort Pitt, after William Pitt the Elder.

As a result, in 1763 local Delawares and Shawnees took part in Pontiac's Rebellion, an effort to drive the British out of the region. The Indians' siege of Fort Pitt began on June 22 1763, but the fort was too strong to be taken by force. In negotiations during the siege, Captain Simeon Ecuyer, the commander of Fort Pitt gave two Delaware emissaries blankets that had been exposed to smallpox, in hopes of infecting the surrounding Indians and ending the siege. The attempt was probably unsuccessful, and on August 1, 1763, most of the Indians broke off the siege in order to intercept an approaching force under Colonel Henry Bouquet, resulting in the Battle of Bushy Run. Bouquet fought off the attack and relieved Fort Pitt on August 20.

After Pontiac's War, Fort Pitt was no longer necessary to the British Crown, and was abandoned to the locals in 1772. At that time, the Pittsburgh area was claimed by both Virginia and Pennsylvania, and a power struggle for the region commenced. Virginians took control of Fort Pitt, and for a brief while in the 1770s it was called Fort Dunmore, in honour of Virginia's Governor Lord Dunmore. The fort served as a staging ground in Dunmore's War of 1774.

During the American Revolutionary War, Fort Pitt served as a headquarters for the western theatre of the war.

A small brick building called the Blockhouse—actually an outbuilding known as a redoubt—remains in Point State Park, the only intact remnant of Fort Pitt. It was erected in 1764, and is believed to be the oldest building, not only in Pittsburgh, but in western Pennsylvania. Used for many years as a house, the blockhouse was purchased and has been preserved for many years by the Daughters of the American Revolution, who make it open to the public. Part of the foundations of Fort Pitt have been excavated and some of the fort has been rebuilt, though, giving visitors to Point Park a sense of the size of the fort. In this rebuilt section the Monongahela Bastion houses the Fort Pitt Museum.It should be noted that the excavated portions of the fort have been filled in and are no longer accessible by the public, despite outrage from local citizens. The city of Pittsburgh thought the land would be better used as solid ground. However, the rebuilt section containing the Fort Pitt Museum and the Blockhouse still stand.
Fort Pitt Foundry was an important armaments manufacturing center for the Federal government during the Civil War, under the charge of William Metcalf.

See also

• Great Britain in the Seven Years War