About Pittsburgh

Pittsburgh ( PITS-burg) is a city in the Commonwealth of Pennsylvania and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylvania after Philadelphia, and the 68th-most populous city in the U.S. with a population of 302,971 as of the 2020 census. The city anchors the Greater Pittsburgh metropolitan area of Western Pennsylvania; its population of 2.37 million is the largest in both the Ohio Valley and Appalachia, the second-largest in Pennsylvania, and the 27th-largest in the U.S. It is the principal city of the greater Pittsburgh–New Castle–Weirton combined statistical area that extends into Ohio and West Virginia. Pittsburgh is located in southwest Pennsylvania at the confluence of the Allegheny River and the Monongahela River, which combine to form the Ohio River. Pittsburgh is known both as "the Steel City" for its dominant role in the history of the U.S. steel industry, and as the "City of Bridges" for its 446 bridges.