Location within the U.S. state of Pennsylvania
Pennsylvania's location within the U.S.
|Founded||September 24, 1788|
|Named for||Allegheny River|
|• Total||745 sq mi (1,930 km2)|
|• Land||730 sq mi (1,900 km2)|
|• Water||14 sq mi (40 km2) 1.9%%|
| • Estimate |
|• Density||1,666/sq mi (643/km2)|
|Time zone||UTC−5 (Eastern)|
|• Summer (DST)||UTC−4 (EDT)|
|Congressional districts||17th, 18th|
|Designated||December 30, 1982|
Allegheny County (//) is a county in the southwest of the U.S. state of Pennsylvania. As of 2019 the population was 1,216,045, making it the state's second-most populous county, following Philadelphia County. The county seat is Pittsburgh. Allegheny County is included in the Pittsburgh, PA Metropolitan Statistical Area, and in the Pittsburgh Designated Market Area.
Allegheny was Pennsylvania's first county to bear a Native American name, being named after the Allegheny River. The word "Allegheny" is of Lenape origin, with uncertain meaning. It is usually said to mean "fine river", but sometimes said to refer to an ancient mythical tribe called "Allegewi" that lived along the river before being destroyed by the Lenape.
Little is known of the region's inhabitants prior to European contact. During the colonial era, various native groups claimed or settled in the area, resulting in a multi-ethnic mix that included Iroquois, Lenape, Shawnee, and Mingo. European fur traders such as Peter Chartier established trading posts in the region in the early eighteenth century.
In 1749, Captain Pierre Joseph Céloron de Blainville claimed the Ohio Valley and all of western Pennsylvania for Louis XV of France. The captain traveled along the Ohio and Allegheny rivers inserting lead plates in the ground to mark the land for France.
Since most of the towns during that era were developed along waterways, both the French and the British desired control over the local rivers. Therefore, the British sent Major George Washington to expel the French from their posts, with no success. Failing in this objective, he nearly drowned in the ice-filled Allegheny River while returning. The English tried in 1754 to again enter the area. They sent 41 Virginians to build Fort Prince George. The French learned of the plan and sent an army to capture the fort, which they then resumed building with increased fortification, renaming it Fort Duquesne.
The loss cost the English dearly because Fort Duquesne became a focal point of the French and Indian War. The first attempt to retake the fort, the Braddock Expedition, failed miserably. It was recaptured in 1758 by British forces under General John Forbes; he had it destroyed after its capture. The British then built a new, larger fort on the site, including a moat, and named it Fort Pitt. The site is now Pittsburgh's Point State Park.
Both Pennsylvania and Virginia claimed the region that is now Allegheny County. Pennsylvania administered most of the region as part of its Westmoreland County. Virginia considered everything south of the Ohio River and east of the Allegheny River to be part of its Yohogania County and governed it from Fort Dunmore. In addition, parts of the county were located in the proposed British colony of Vandalia and the proposed U.S. state of Westsylvania. The overlapping boundaries, multiple governments, and confused deed claims soon proved unworkable. In 1780 Pennsylvania and Virginia agreed to extend the Mason–Dixon line westward, and the region became part of Pennsylvania. From 1781 until 1788, much of what had been claimed as part of Yohogania County, Virginia, was administered as a part of the newly created Washington County, Pennsylvania.
Allegheny County was officially created on September 24, 1788, from parts of Washington and Westmoreland counties. It was formed due to pressure from settlers living in the area around Pittsburgh, which became the county seat in 1791. The county originally extended north to the shores of Lake Erie; it was reduced to its current borders by 1800.
In the 1790s, a whiskey excise tax was imposed by the United States federal government. This started the so-called Whiskey Rebellion when the farmers who depended on whiskey income refused to pay and drove off tax collector John Neville. After a series of demonstrations by farmers, President George Washington sent troops to stop the rebellion.
The area developed rapidly in the 1800s to become the nation's prime steel producer; Pittsburgh gained the label "Steel Capital of the World".
In 1913 the County's 125th anniversary was celebrated with a week long chain of events, the final day September 27 was marked with a steamboat parade consisting of 30 paddle wheelers which sailed from Monongahela Wharf down the Ohio to the Davis Island Dam. The boats in line were the Steel City (formerly the Pittsburgh and Cincinnati packet Virginia), the flag ship; City of Parkersburg, Charles Brown, Alice Brown, Exporter, Sam Brown, Boaz, Raymond Horner, Swan, Sunshine, I. C. Woodward, Cruiser, Volunteer, A. R. Budd, J. C. Risher, Clyde, Rival, Voyager, Jim Brown, Rover, Charlie Clarke, Robt. J. Jenkins, Slipper, Bertha, Midland Sam Barnum, Cadet, Twilight, and Troubadour.
Three majors traverse Allegheny County: the Allegheny River and the Monongahela River converge at Downtown Pittsburgh to form the Ohio River. The Youghiogheny River flows into the Monongahela River at McKeesport, 10 miles (16 km) southeast. There are several islands in these courses. The rivers drain into the Gulf of Mexico via the Mississippi River. Although the county's industrial growth caused the clearcutting of the area's forests, a significant woodland remains.
Allegheny has a humid continental climate which is hot-summer (Dfa) except in higher areas where it is warm-summer (Dfb).
|Climate data for Pittsburgh (Pittsburgh International Airport), 1981–2010 normals,[a] extremes 1871–present[b]|
|Record high °F (°C)||75
|Mean maximum °F (°C)||59.7
|Average high °F (°C)||35.7
|Average low °F (°C)||21.1
|Mean minimum °F (°C)||−0.1
|Record low °F (°C)||−22
|Average precipitation inches (mm)||2.70
|Average snowfall inches (cm)||11.5
|Average precipitation days (≥ 0.01 in)||16.2||13.6||14.0||13.8||13.3||12.1||10.2||9.8||9.8||10.5||12.8||15.1||151.2|
|Average snowy days (≥ 0.1 in)||11.4||8.3||5.9||2.0||0||0||0||0||0||0.3||3.0||8.5||39.4|
|Average relative humidity (%)||69.9||67.3||64.1||59.8||63.4||66.2||68.8||71.2||72.0||68.3||70.2||71.9||67.8|
|Mean monthly sunshine hours||93.9||108.5||155.4||182.8||217.4||242.2||254.9||228.4||196.7||167.3||99.4||74.4||2,021.3|
|Percent possible sunshine||31||36||42||46||49||54||56||54||53||48||33||26||45|
|Average ultraviolet index||2||3||4||6||8||9||9||8||6||4||2||2||5|
|Source 1: NOAA (relative humidity and sun 1961–1990)|
|Source 2: Weather Atlas |
Until January 1, 2000, Allegheny County's government was defined under Pennsylvania's Second Class County Code. The county government was charged with all local activities, including elections, prisons, airports, public health, and city planning. All public offices were headed by elected citizens. There were three elected county commissioners.
On January 1, 2000, the Home-Rule Charter went into effect. It replaced the three elected commissioners with an elected chief officer (the County Executive), a county council with 15 members (13 elected by district, two elected county-wide), and an appointed county manager. The changes were intended to maintain a separation of powers between the executive and legislative branches while providing greater citizen control.
The county has 130 self-governing municipalities, the most in the state. (Luzerne is second with 76). The county has one Second Class City (Pittsburgh) and three Third Class Cities (Clairton, Duquesne, and McKeesport).
A 2004 study found the county would be better served by consolidating the southeastern portion of the county (which includes many small communities with modest economies) into a large municipality ("Rivers City") with a combined population of approximately 250,000.
Under the Onorato administration, Allegheny County paid $10,000 per month to Robert Ewanco, of Greenlee Partners, to lobby the Pennsylvania General Assembly. County officials credit him with a "20-fold" return in the form of appropriations for a widening project on Pennsylvania Route 28, as well as a footbridge and security cameras at Duquesne University.
As of November 7, 2017, there were 921,861 registered voters in the county; a majority were Democrats. There were 536,248 registered Democrats, 258,340 registered Republicans, 120,994 voters registered to other parties, 4,929 to the Libertarian Party and 1,350 voters registered to the Green Party.
|Voter registration and party enrollment|
|Party||Number of voters||Percentage|
As of April 27, 2020, there were 895,158 registered voters in the county; a majority were Democrats. There were 521,327 registered Democrats, 249,831 registered Republicans, 79,490 voters registered as No Affiliation Voters and 44,510 registered to other parties. 
|Voter registration and party enrollment|
|Party||Number of voters||Percentage|
The Republican Party had been historically dominant in county-level politics in the 19th and early 20th centuries; prior to the Great Depression, Pittsburgh and Allegheny County had been majority Republican. Since the Great Depression on the state and national levels, the Democratic Party has been dominant in county-level politics and is the Democratic stronghold of western Pennsylvania. In 2000, Democrat Al Gore won 56% of the vote and Republican George W. Bush won 41%. In 2004, Democrat John Kerry received 57% of the vote and Republican Bush received 42%. In 2006, Democrats Governor Ed Rendell and Senator Bob Casey, Jr. won 59% and 65% of the vote in Allegheny County, respectively. In 2008, Democrat Barack Obama received 57% of the vote, John McCain received 41%, and each of the three state row office winners (Rob McCord for Treasurer, Jack Wagner for Auditor General, and Tom Corbett for Attorney General) also carried Allegheny. In 2016, despite Donald Trump being the first Republican to carry Pennsylvania since 1988, Hillary Clinton did slightly better than Barack Obama's 2012 vote total while Donald Trump was the worst performing Republican in 20 years. In the 2018 Midterms, Democrats received an even higher percentage of the vote with Tom Wolf and Bob Casey receiving approximately two thirds of the county's vote. This is an improvement over the approximately 55% each person received in the county in their last election in 2014 and 2012 respectively.
In 2010 statistics, the largest religious group in Allegheny County was the Diocese of Pittsburgh, with 460,672 Catholics worshipping at 179 parishes, followed by 44,204 UMC Methodists with 100 congregations, 42,838 PC-USA Presbyterians with 145 congregations, 33,103 non-denominational adherents with 85 congregations, 24,718 ELCA Lutherans with 77 congregations, 17,148 ABCUSA Baptists with 42 congregations, 12,398 AoG Pentecostals with 30 congregations, 8,483 Reform Jews with 6 congregations, 7,780 TEC Episcopalians with 19 congregations, and 6,700 Hindus with two temples. Altogether, 60.6% of the population was claimed as members by religious congregations, although members of historically African-American denominations were underrepresented due to incomplete information. In 2014, Allegheny County had 794 religious organizations, the 11th most out of all US counties.
|U.S. Decennial Census|
As of the 2010 census, there were 1,223,348 people living in the county. The population density was 1676 people per square mile (647/km²). The racial makeup of the county was 82.87% White, 14.39% Black or African American, 2.94% Asian, 0.03% Pacific Islander, 0.37% from other races, and 1.40% from two or more races. About 1.31% of the population were Hispanic or Latino of any race.
At the census of 2000, there were 1,281,666 people, 537,150 households, and 332,495 families living in the county. The population density was 1,755 people per square mile (678/km²). There were 583,646 housing units at an average density of 799 per square mile (309/km²). The racial makeup of the county was 84.33% White, 12.41% Black or African American, 0.12% Native American, 1.69% Asian, 0.03% Pacific Islander, 0.34% from other races, and 1.07% from two or more races. About 0.87% of the population were Hispanic or Latino of any race. 20.0% were of German, 15.0% Italian, 12.7% Irish, 7.5% Polish and 5.1% English ancestry according to Census 2000. 93.5% spoke English and 1.3% Spanish as their first language.
There were 537,150 households out of which 26.40% had children under the age of 18 living with them, 46.10% were married couples living together, 12.40% had a female householder with no husband present, and 38.10% were non-families. Some 32.70% of all households were made up of individuals and 13.20% had someone living alone who was 65 years of age or older. The average household size was 2.31 and the average family size was 2.96.
The age distribution of the population shows 21.90% under the age of 18, 8.50% from 18 to 24, 28.30% from 25 to 44, 23.40% from 45 to 64, and 17.80% who were 65 years of age or older. The median age was 40. For every 100 females, there were 90.00 males; for every 100 females age 18 and over, there were 86.20 males.
In the late 18th century farming played a critical role in the growth of the area. There was a surplus of grain due to transportation difficulties in linking with the eastern portion of the state. As a result, the farmers distilled the grain into whiskey, which significantly helped the farmers financially.
The area quickly became a key manufacturing area in the young nation. Coupled with deposits of iron and coal, and the easy access to waterways for barge traffic, the city quickly became one of the most important steel producing areas in the world. Based on 2007 data from the US Army Corps of Engineers, Pittsburgh is the second (after Laredo, Texas) busiest inland port in the nation.
US steel production declined late in the 20th century, and Allegheny County's economy began a shift to other industries. It is presently known for its hospitals, universities, and industrial centers. Despite the decline of heavy industry, Pittsburgh is home to a number of major companies and is ranked in the top ten among US cities hosting headquarters of Fortune 500 corporations, including U.S. Steel Corporation, PNC Financial Services Group, PPG Industries, and H. J. Heinz Company.
The Commonwealth of Pennsylvania has 36 Approved Private Schools including the Charter Schools for the Blind and Deaf. The private schools are licensed by the State Board of Private Academic Schools. They provide a free appropriate special education for students with severe disabilities. The cost of tuition for these schools is paid 60% by the state and 40% by the local school district where the student is a resident. Pennsylvania currently has four PA chartered and 30 non-charter APSs for which the Department approves funding. These schools provide a program of special education for over 4,000 day and residential students. Parents are not charged for the services at the school. In 2009, the Pennsylvania Department of Education budgeted $98 million for the tuition of children in approved private schools and $36.8 million for students attending the charter schools for the deaf and blind. The majority of these schools are located in the southeastern region and southwestern region of Pennsylvania.
These are state-designated before- and after-school program providers. They receive state funding through grants. CCLCs provide academic, artistic and cultural enhancement activities to students and their families when school is not in session.
Allegheny County's public transportation provider is the Port Authority of Allegheny County. The Allegheny County Department of Public Works oversees infrastructure, maintenance, and engineering services in the county.
The Three Rivers Heritage Trail provides uninterrupted bicycle and pedestrian connections along the three rivers in the city, and the Great Allegheny Passage trail runs from downtown Pittsburgh to Washington, D.C.
The Allegheny County Airport is the original airport for Pittsburgh and houses a number of flight schools, charter flight operations, and medevac operations.
For information about major state roads, see list of State Routes in Allegheny County, Pennsylvania and Allegheny County Belt System.
There are two Pennsylvania state parks in Allegheny County. Point State Park is at the confluence of the Allegheny and Monongahela rivers in Downtown Pittsburgh, and Allegheny Islands State Park is in the Allegheny River in Harmar Township and is undeveloped as of August 2010.
Census-designated places are geographical areas designated by the US Census Bureau for the purposes of compiling demographic data. They are not actual jurisdictions under Pennsylvania law. Other unincorporated communities, such as villages, may be listed here as well.
Many political subdivisions of Allegheny County have come and gone through subdivision or annexation through the years. These include:
† county seat
|Rank||City/Town/etc.||Population (2010 Census)||Municipal type||Incorporated|
|1||† Pittsburgh||305,704||City||1794 (borough) 1816 (city)|
|2||Penn Hills||42,329||Municipality||1851 (Penn Twp.) 1958 (Penn Hills Twp.) 1976 (municipality)|
|3||Mt. Lebanon||33,137||Municipality||1912 (township) 1975 (municipality)|
|4||Bethel Park||32,313||Municipality||1949 (borough) 1978 (municipality)|
|7||Plum||27,126||Borough||1788 (township) 1956 (borough)|
|11||McKeesport||19,731||City||1842 (borough) 1891 (city)|
|12||Wilkinsburg||15,930||Borough||1871 (Sterrett Twp.) 1887 (borough)|
|27||Clairton||6,796||City||1903 (borough) 1922 (city)|
|34||Duquesne||5,565||City||1891 (borough) 1918 (city)|
|53||Trafford (mostly in Westmoreland County)||3,174||Borough||1904|
|66||McDonald (mostly in Washington County)||2,149||Borough||1889|
|106||Ben Avon Heights||371||Borough||1913|
|Wikivoyage has a travel guide for Allegheny County.|
|Wikimedia Commons has media related to Allegheny County, Pennsylvania.|