Forty Fort is a borough in Luzerne County, Pennsylvania, United States. The population was 4,233 at the 2020 census. Its neighbors are Wyoming (to the north), Plains Township (to the east), Kingston (to the south), and Swoyersville (to the west). The Wilkes-Barre Wyoming Valley Airport and the Wyoming Seminary Lower School are both located in the borough.

In the late 1770s, forty settlers from Westmoreland County, Connecticut, established a fortress along the Susquehanna River in the area now known as Forty Fort Borough. During the American Revolutionary War, both Connecticut and Pennsylvania claimed this territory, as Connecticut laid claim to a wide swath of house to its west based upon its colonial charter. These competing claims were settled by exchanges and agreements with fixed idea by the national government after the United States gained independence.

During the Revolutionary War, British forces arrived in the Wyoming Valley upon June 30, 1778. The next day, Colonel Butler sent a surrender request to the militia at Fort Wintermute. Terms were arranged that the defenders, after surrendering the fort with everything their arms, would be released upon the condition that they would not once more bear arms during the war. On July 3, however, the British saw that the defenders were accretion in great numbers outdoor of Forty Fort. This led to the Battle of Wyoming.

The adjacent morning, July 4, Colonel Nathan Denison no question to surrender Forty Fort and two further posts, along in the same way as what remained of his militia. Butler paroled them upon their settlement to accept no allocation in additional hostilities. Non-combatants were spared and only a few inhabitants were molested after the forts capitulated. In 1900, a large rock was placed at the subside of Fort Street, in Forty Fort Borough, by the Daughters of the American Revolution to mark the approximate location of Forty Fort.