St. Clair Township,

Allegheny County, Pennsylvania Allegheny County () is a county in the Commonwealth of Pennsylvania. It is located in Southwestern Pennsylvania. As of the 2020 census, the population was 1,250,578, making it the state's second-most populous county, following Philadelphia Co ...

, was one of the original townships created with the incorporation of Allegheny

County A county is a geographic region of a country used for administrative or other purposesChambers Dictionary, L. Brookes (ed.), 2005, Chambers Harrap Publishers Ltd, Edinburgh in certain modern nations. The term is derived from the Old French ...

in 1788. The township was named after Arthur St. Clair, an

American Revolutionary War The American Revolutionary War (April 19, 1775 – September 3, 1783), also known as the Revolutionary War or American War of Independence, was a major war of the American Revolution. Widely considered as the war that secured the independence of t ...

general A general officer is an Officer (armed forces), officer of highest military ranks, high rank in the army, armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers t ...

and president of the

Continental Congress The Continental Congress was a series of legislative bodies, with some executive function, for thirteen of Britain's colonies in North America, and the newly declared United States just before, during, and after the American Revolutionary War. ...

in 1787. The township extended from the

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

and Monongahela rivers to the southern county line. It was bounded on the west by

Chartiers Creek Chartiers Creek is a tributary of the Ohio River in Western Pennsylvania in the United States. The creek was named after Peter Chartier, a trapper of French and Native American parentage who established a trading post at the mouth of the cree ...

and on the east partially by

Streets Run Streets Run is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 tributary of the Monongahela River in Allegheny County, Pennsylvania. This urban stream drains portions ...

. The township was subsequently divided between the northern part, Lower St. Clair Township, and the southern part, Upper St. Clair Township. The "upper" and "lower" referred to the

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...

, as Lower St. Clair bordered on the

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

, the lowest elevation, and Upper St. Clair extended into the South Hills of Pittsburgh. The original Lower St. Clair Township consisted of the present-day neighborhoods of the City of Pittsburgh south of the Monongahela and Ohio, and all or parts of Green Tree, Carnegie, Baldwin, Bridgeville, Dormont, Mount Lebanon and other boroughs and townships in the South Hills. The township was subdivided several times, and today exists only as the neighborhood of St. Clair in the City of Pittsburgh. Upper St. Clair Township, subdivided many times, still exists in the South Hills of Pittsburgh.

References

{{Pittsburgh, Allegheny County, Pennsylvania Former townships in Allegheny County, Pennsylvania