Allegheny County, Pennsylvania

Allegheny County: County in the southwestern part of the U.S. state of Pennsylvania


Allegheny County is a county located in the U.S. state of Pennsylvania. As of the 2010 census, the population was 1,223,348 and a population density of 634 people per km². After 10 years in 2020 county had an estimated population of 1,211,358 inhabitants. Its county seat is Pittsburgh. The county was created 235 years ago in 1788.

Allegheny County locator map
Location of Allegheny County on Pennsylvania map.

Quick Facts about Allegheny County

Population : 1,211,358 (2020)
Country : United States of America
State : Pennsylvania (United States)
Different from : Anderson County, Allen County, Anderson County, Allen County, Alleghany County, Anderson County, Allegany County, Anderson County, Allen Parish, Allegan County, Alleghany County, Allen County, Allen County, Allegany County, Anderson County
Area : 1929 km2
Official name : Allegheny County
Water as percent of area : 1.9%
Land as percent of area : 98.1%
Named for : Allegheny River
Altitude : 961 feet / 293 meters
Capital : Pittsburgh
Establishment : September 09, 1788
Time Zone : America/New_York
Local time : 14:32:01 (17th April 2024)
Density : 628 Pop. per km² as of 2020
Population growth : -0.99% (2010-2020)
AlleghenyCountyCourthouse image
AlleghenyCountyCourthouse image


Allegheny County is located at 40°28'8"N 79°58'52"W (40.4688300, -79.9811900). It has 4 neighbors: Armstrong County, Butler County, Washington County and Westmoreland County.

Allegheny County map

The largest city of Allegheny County is Pittsburgh with a population of 299,226. Other cities include, Penn Hills population 40,517, Municipality of Bethel Park population 32,345, Bethel Park population 32,118 and Mount Lebanon population 31,418. See all Allegheny County cities & populated places.

Allegheny County Populated Places (more)

Cities, towns, neighborhoods & other populated places in Allegheny County.

City Name Population Title
Pittsburgh 299,226 The second most populous city in Pennsylvania and the center of the Pittsburgh metropolitan area.
Penn Hills 40,517 A borough in Allegheny County, Pennsylvania.
Bethel Park 32,118 Home rule municipality of Pennsylvania
Mount Lebanon 31,418 Municipality in Pennsylvania
Monroeville 28,176 City in Alabama, United States
Plum 26,993 Borough of Pennsylvania
Moon 25,204 Township in Allegheny County, Pennsylvania
Unity 21,600 Township in Westmoreland County, Pennsylvania, United States
Upper Saint Clair 19,896 Home rule municipality in Allegheny County
West Mifflin 19,588 Borough of Pennsylvania
McKeesport 18,927 City in Allegheny County, Pennsylvania, United States
Wilkinsburg 15,186 Borough of Pennsylvania
Franklin Park 14,883 Borough of Pennsylvania
Cecil 13,220 Township in Washington County, Pennsylvania
Elizabeth 11,494 Borough in Pennsylvania, United States
Jefferson Hills 11,136 Borough of Pennsylvania

Allegheny County has 4 neighbours.


According to census records, the population of Allegheny County decreased by 0.99% in 10 years.

Year Population % Change Method
2010 1,223,348 - census
2011 1,228,297 0.4% estimation process
2012 1,230,911 0.21% estimation process
2013 1,233,700 0.23% estimation process
2014 1,233,027 -0.05% estimation process
2015 1,228,827 -0.34% estimation process
2016 1,226,426 -0.2% estimation process
2017 1,220,141 -0.52% estimation process
2018 1,217,281 -0.23% estimation process
2019 1,216,045 -0.1% estimation process
2020 1,211,358 -0.39% estimation process

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People born in Allegheny County (38)

People born in Allegheny County, including horticulturist Alex Shigo, historian, toponymist, and novelist George R. Stewart, actor/film director Lois Weber, .


  • Bunny Yeager (American photographer and model) she was born in 13/03/1929
  • Alferd Packer (Union Army soldiers) he was born in 21/01/1842
  • Sidney Rigdon (American Mormon leader) he was born in 19/02/1793
  • William D. Boyce (Businessman and founder of Scouting in America) he was born in 16/06/1858
  • Elijah Hise (American politician (1802-1867)) he was born in 04/07/1802
  • Joseph M. Schmondiuk (Archbishop of the Ukrainian Catholic Church) he was born in 06/08/1912
  • Philip Childs Keenan (American astronomer) he was born in 31/03/1908
  • Michael Dietz (American actor) he was born in 10/02/1971
  • Charlie Batch (former NFL quarterback) he was born in 05/12/1974
  • Mary Ruefle (Poet, essayist, professor) she was born in 16/04/1952
  • M. Graham Netting (American zoologist) he was born in 01/01/1904
  • Terrell Anderson he was born in 29/11/1989
  • Baptiste Manzini (American football player and coach (1920-2008)) he was born in 27/08/1920
  • Charles Mertz Arbuthnot (physician and pharmacist in Kansas) he was born in 15/12/1852
  • Edward Early (American politician) he was born in 02/10/1935
  • Justin Kurpeikis (American football player) he was born in 17/07/1977
  • James Y. McKee (Acting president of Penn State University) he was born in 20/06/1836
  • Jim Callahan (American baseball player) he was born in 12/01/1881

Pennsylvania Other Counties (more counties)

County Name Population Title
Philadelphia County 1,578,487 County in Pennsylvania, United States
Philadelphia 1,578,487 The sixth most populous city in the United States and the center of the Philadelphia metropolitan area.
Montgomery County 833,869 County in Pennsylvania, United States
Bucks County 627,987 County in Pennsylvania, United States
Delaware County 566,753 County in Pennsylvania, United States
Lancaster County 546,192 County in Pennsylvania, United States
Chester County 526,759 County in Pennsylvania, United States
York County 450,448 County in Maine, United States
Berks County 421,017 County in Pennsylvania, United States
Lehigh County 370,802 County in Pennsylvania, United States of America
Westmoreland County 347,087 County in Pennsylvania, United States
Luzerne County 316,982 County in Pennsylvania, United States
Northampton County 305,892 County in Pennsylvania, United States
Pittsburgh 299,226 The second most populous city in Pennsylvania and the center of the Pittsburgh metropolitan area.
Dauphin County 279,874 County in Pennsylvania, United States
Erie County 268,426 County in Pennsylvania, United States