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, after Philadelphia County. Its county seat is Pittsburgh.
Allegheny County is part of the Pittsburgh, PA metropolitan statistical area and the Pittsburgh media market.
Allegheny was the first county in Pennsylvania to be given a Native American name. It was named after the Lenape word for the Allegheny River. The meaning of "Allegheny" is uncertain.
Wikipedia https://en.wikipedia.org/wiki/Allegheny_County,_Pennsylvania
Coordinates 40°26'30.098" N -79°59'24.31" E