Western Pennsylvania in the context of "Allegheny River"

Pittsburgh (/ˈpɪtsbɜːrɡ/ PITS-burg) is a city in Allegheny County, Pennsylvania, United States, and its county seat. Located in southwestern Pennsylvania where the Allegheny and Monongahela Rivers meet to form the Ohio River, it had a population of 302,971 at the 2020 census, making it the second-most populous city in Pennsylvania. The Pittsburgh metropolitan area has over 2.43 million people, making it the largest in the Ohio Valley and Appalachia, the second-largest in Pennsylvania, and the 28th-largest in the U.S. The greater Pittsburgh–Weirton–Steubenville combined statistical area includes parts of Ohio and West Virginia.

Pittsburgh is known as "the Steel City" for its dominant role in the history of the U.S. steel industry. It developed as a vital link of the Atlantic coast and Midwest, as the mineral-rich Allegheny Mountains led to the region being contested by the French and British empires, Virginians, Whiskey Rebels, and Civil War raiders. For part of the 20th century, Pittsburgh was behind only New York City and Chicago in corporate headquarters employment; it had the most U.S. stockholders per capita. Deindustrialization in the late 20th century resulted in massive layoffs among blue-collar workers as steel and other heavy industries declined, coinciding with several Pittsburgh-based corporations moving out of the city. However, the city divested from steel and, since the 1990s, Pittsburgh has focused its energies on the healthcare, education, and technology industries.

The Diocese of Pittsburgh (Latin: Diœcesis Pittsburgensis) is a diocese of the Catholic Church in Western Pennsylvania in the United States. It was established on August 11, 1843. The diocese is a suffragan diocese of the Archdiocese of Philadelphia. The cathedral church is Saint Paul Cathedral in Pittsburgh. The bishop of Pittsburgh is Mark Eckman.

Mercer County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 110,652. Its county seat is Mercer, and its largest city is Hermitage. The county is part of the Northwest region of the commonwealth.

Mercer County compromises the Hermitage, PA Micropolitan Statistical Area, which is included in the Greater Pittsburgh area.

Greater Pittsburgh is the metropolitan area surrounding the city of Pittsburgh in Western Pennsylvania, United States. The region includes Allegheny County, Pittsburgh's urban core county and economic hub, and seven adjacent Pennsylvania counties: Armstrong, Beaver, Butler, Fayette, Lawrence, Washington, and Westmoreland in Western Pennsylvania, which constitutes the Pittsburgh, PA Metropolitan Statistical Area MSA as defined by the U.S. Office of Management and Budget.

As of the 2020 census, the Greater Pittsburgh region had a population of over 2.45 million people. Pittsburgh, the region's core city, has a population of 302,971, the second-largest in the state after Philadelphia. Over half of the region's population resides within Allegheny County, which has a population of 1.24 million and is the state's second-largest county after Philadelphia County.