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Pittsburgh Low Plateau

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About the Pittsburgh Low Plateau

The Pittsburgh Low Plateau is the northeasternmost region within the Western Allegheny Plateau, and is mostly located within western Pennsylvania, with a small piece extending into eastern Ohio.

This region is a well-dissected plateau, flat on a large scale, but locally hilly, with rounded hills, narrow valleys. Hilltops range from 1,100 to 1,400 feet (366-396m). Elevations tend to be lower than areas to the east and north, but higher than areas to the west.

The original forest cover here was probably mostly Appalachian oak forest with some mixed mesophytic forest in the south.

This area has been heavily developed for agriculture, which is interspersed with numerous small fragments of forest. There has also been significant mining of bituminous coal, which is abundant in this region, and there are some oil wells and gas fields as well. Some forests exist on abandoned mining sites. There is also significant urbanization and industry. This area contains part of the Pittsburgh metro area as well as some smaller cities; Pittsburgh lies on the southwest border of this region and part of its urban area extends into the neighboring Monongahela Transition Zone.

Acid mine drainage and other industrial pollution has degraded the waterways in this region, although the damage has been greater for fish populations than terrestrial plant life.

This region is bordered to the southwest by the Monongahela Transition Zone, which is somewhat irregularly interspersed with this region in the southeast. To the west, there is a small border with the Unglaciated Upper Muskingum Basin. To the northwest lies the Low Lime Drift Plain. To the north, this region borders the higher-altitude Unglaciated High Allegheny Plateau. To the east also lie higher-altitude areas, the Uplands and Valleys of Mixed Land Use in the north and the even higher-elevation Forested Hills and Mountains south of that.

This photo, taken near East Brady, PA, shows the Allegheny river, a major feature in this region, winding through a typical landscape that is locally hilly but flat over a large spatial scale. Photo © Nyttend (Wikipedia), Public Domain.


1. Woods, A.J, Omernik, J.M., Brown, D.D. "Level III and IV Ecoregions of Delaware, Maryland, Pennsylvania, Virginia, and West Virginia", U.S. Environmental Protection Agency: National Health and Environmental Effects Research Laboratory, Corvallis, OR (1999) Web.