Pittsburgh is the region's principal city, with a metropolitan area population of about 2.4 million people, and serves as its economic and cultural center.

[1] Although the Commonwealth does not designate Western Pennsylvania as an official region, since colonial times it has retained a distinct identity not only because of its geographical distance from Philadelphia, the beginning of Pennsylvania settlement, but also and especially because of its topographical separation from the east by virtue of the Appalachian Mountains, which characterize much of the western region.

The strong cultural identity of Western Pennsylvania is reinforced by the state supreme court holding sessions in Pittsburgh, in addition to Harrisburg and Philadelphia.

In alphabetical order those counties are: Long recognized as a powerhouse of American industry, Western Pennsylvania is a large geophysical and socio-economic entity.

It encompasses that portion of the state to the west of the Appalachian divide and included within the Mississippi drainage system of rivers.

Incredibly, after several decades of border war and 150 years of high-rent city-center urbanization, the original 1764 blockhouse from Fort Pitt still stands here and is one of the oldest buildings in the region.