|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%%|
|• Density||1,713/sq mi (661/km2)|
|Time zone||UTC−5 (Eastern)|
|• Summer (DST)||UTC−4 (EDT)|
|Congressional districts||17th, 18th|
|Designated||December 30, 1982|
Allegheny County (//) is located in the southwest of the U.S. state of Pennsylvania. As of the 2020 census, the population was 1,250,578, 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 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. It is usually said to mean "fine river". Stewart says that the name may come from a Lenape account of an ancient mythical tribe called "Allegewi", who lived along the river before being taken over by the Lenape.
Prior to European contact, this area was settled for thousands of years by succeeding cultures of indigenous peoples. During the colonial era, historic native groups known by the colonists to settle in the area included members of western nations of the Iroquois, such as the Seneca; the Lenape, who had been pushed from the East by European-American settlers; the Shawnee, who also had territory in Ohio; and the Mingo, a group made up of a variety of peoples from more eastern tribes.
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 King Louis XV of France. The captain traveled along the Ohio and Allegheny rivers. He installed lead plates in the ground to mark the land for France.
Most of the towns during that era were developed along waterways, which were the primary transportation routes, as well as providing water for domestic uses. Through the eighteenth century, both the French and the British competed for control over the local rivers in this frontier territory of North America. Native American bands and tribes allied with the colonists to differing degrees, often based on their trading relationships. The British sent Major George Washington to expel the French from their posts, with no success. He also nearly drowned in the ice-filled Allegheny River while returning to camp.
The English tried again in 1754 to establish a post in 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. They resumed building it and added increased defensive fortification, renaming it as Fort Duquesne.
Given its strategic location at the Ohio, Fort Duquesne became an important focal point of the French and Indian War. The first British attempt to retake the fort, the Braddock Expedition, failed miserably. In 1758 British forces under General John Forbes recaptured the fort; he had it destroyed to prevent any use by the French. The British built a new, larger fort on the site, including a moat, and named it Fort Pitt. The historic site has been preserved as Pittsburgh's Point State Park.
Under their colonial charters, 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. Near the end of the American Revolutionary War, in 1780 Pennsylvania and Virginia agreed to extend the Mason–Dixon line westward. This region was assigned to Pennsylvania. From 1781 until 1788, much of what Virginia had claimed as part of Yohogania County 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 to respond to pressure from the increase in settlers living in the area around Pittsburgh; this was designated as 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. As population increased in the territory, other counties were organized.
In the 1790s, the United States federal government imposed a whiskey excise tax. Farmers who had depended on whiskey income refused to pay and started the so-called Whiskey Rebellion after driving off tax collector John Neville. After a series of demonstrations by farmers, President George Washington sent troops to suppress the frontier rebellion.
The area developed rapidly through the 1800s with industrialization. It became the nation's prime steel producer by the late 19th century and Pittsburgh was nicknamed "Steel Capital of the World".
In 1913 the county's 125th anniversary was celebrated with a week-long series of events. The final day, September 27, was marked by a steamboat parade of 30 paddle wheelers. They traveled 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.
According to the U.S. Census Bureau, the county has a total area of 745 square miles (1,930 km2), of which 730 square miles (1,900 km2) is land and 14 square miles (36 km2) (1.9%) is water.
Three major rivers 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) to the southeast. There are several islands in these courses. The rivers drain via the Mississippi River into the Gulf of Mexico. Although the county's industrial growth resulted in clearcutting of the area's forests at one time, there has been regrowth and 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), 1991–2020 normals,[a] extremes 1871–present[b]|
|Record high °F (°C)||75
|Mean maximum °F (°C)||61
|Average high °F (°C)||36.3
|Daily mean °F (°C)||28.8
|Average low °F (°C)||21.4
|Mean minimum °F (°C)||1
|Record low °F (°C)||−22
|Average precipitation inches (mm)||2.96
|Average snowfall inches (cm)||13.3
|Average precipitation days (≥ 0.01 in)||16.8||13.9||14.0||13.9||13.5||12.4||11.2||10.5||9.8||11.1||12.0||14.6||153.7|
|Average snowy days (≥ 0.1 in)||12.2||9.3||5.9||1.6||0.0||0.0||0.0||0.0||0.0||0.3||3.3||7.6||40.2|
|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|
|Average dew point °F (°C)||17.2
|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, dew point and sun 1961–1990)|
|Source 2: Weather Atlas (UV)|
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).
As of 1 November 2021,[update] there were 924,235 registered voters in the county; a majority were Democrats. There were 528,465 registered Democrats, 260,535 registered Republicans, 92,334 registered as independents and 42,901 registered with 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. It is by far the most Democratic county in western Pennsylvania. For much of the time between the Great Depression and the turn of the millennium, it was the second-strongest Democratic bastion in Pennsylvania, behind only Philadelphia.
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 41%. 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 2020, Joe Biden improved upon Clinton's performance, receiving the highest vote percentage for a Democrat since Michael Dukakis in 1988 and the most votes for a Democrat since LBJ in 1964.
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.
See also: Economy of Pittsburgh
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 county leads the state in number of defense contractors supplying the U.S. military.
These private schools provide special education for disabled students:
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.
Pennsylvania State Game Lands Number 203 is also located in Allegheny County providing hunting and other activities.
Under Pennsylvania law, there are four types of incorporated municipalities: cities, boroughs, townships, and (in one case) a town. The following municipalities are in Allegheny County:
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:
The population ranking of the following table is based on the 2010 census of Allegheny County.
† 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)|
|29||Clairton||6,796||City||1903 (borough) 1922 (city)|
|36||Duquesne||5,565||City||1891 (borough) 1918 (city)|
|55||Trafford (mostly in Westmoreland County)||3,174||Borough||1904|
|68||McDonald (mostly in Washington County)||2,149||Borough||1889|
|108||Ben Avon Heights||371||Borough||1913|