Fort Pitt was a fort built by British colonists during the Seven Years' War at the confluence of the Monongahela and Allegheny rivers, where the Ohio River is formed in western Pennsylvania. It replaced Fort Duquesne, a French colonial fort built in 1754 as tensions increased between Britain and France in Europe and North America. Protection of this area ultimately led to the development of Pittsburgh and Allegheny County, Pennsylvania by British-American colonists and immigrants.