Pittsburgh ( PITS-burg) is a city in the Commonwealth of Pennsylvania and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylvania after Philadelphia, and the 68th-most populous city in the U.S. with a population of 302,971 as of the 2020 census. It is the largest city of the Greater Pittsburgh metropolitan area of Western Pennsylvania; its population of 2.37 million is the largest in both the Ohio Valley and Appalachia, the second-largest in Pennsylvania, and the 27th-largest in the U.S. It is the principal city of the greater Pittsburgh–New Castle–Weirton combined statistical area that extends into Ohio and West Virginia.

Pittsburgh is located in southwest Pennsylvania at the confluence of the Allegheny River and the Monongahela River, which combine to form the Ohio River. Pittsburgh is known both as “the Steel City” for its dominant role in the history of the U.S. steel industry, and as the “City of Bridges” for its 446 bridges. The city features 30 skyscrapers, two inclined railways, a pre-revolutionary fortification and Point State Park at the confluence of the rivers. The city developed as a vital link of the Atlantic coast and Midwest, as the mineral-rich Allegheny Mountains led to the region being contested by the French and British empires, Virginians, Whiskey Rebels, and Civil War raiders.

Aside from steel, Pittsburgh has led in the manufacturing of other important materials—aluminum and glass—and in the petroleum industry. Additionally, it is a leader in computing, electronics, and the automotive industry. For part of the 20th century, Pittsburgh was behind only New York City and Chicago in corporate headquarters employment; it had the most U.S. stockholders per capita. Deindustrialization in the 1970s and 1980s laid off area blue-collar workers as steel and other heavy industries declined, and thousands of downtown white-collar workers also lost jobs when several Pittsburgh-based companies moved out. The population dropped from a peak of 675,000 in 1950 to 370,000 in 1990. However, this rich industrial history left the area with renowned museums, medical centers, parks, research centers, and a diverse cultural district.

After 1990, Pittsburgh transformed into a hub for the health care, education, and technology industries. Pittsburgh is home to large medical providers, including the University of Pittsburgh Medical Center, Allegheny Health Network, and 68 colleges and universities, including research and development leaders Carnegie Mellon University and the University of Pittsburgh. Google, Apple, Denso, Bosch, Meta, Nokia, Autodesk, Amazon, Microsoft, and IBM are among some 1,600 technology firms with a presence in the city, generating $20.7 billion in annual Pittsburgh payrolls.

Federal money has supported the research agenda. The area has served as the federal agency headquarters for cyber defense, software engineering, robotics, energy research and the nuclear navy. In the private sector, Pittsburgh-based PNC is the nation’s fifth-largest bank, and the city is home to eight Fortune 500 companies, and six of the largest 300 U.S. law firms. RAND Corporation, BNY Mellon, Nova, FedEx, Bayer, and the National Institute for Occupational Safety and Health have regional headquarters and offices that helped Pittsburgh become the sixth-best area for U.S. job growth.

In 2015, Pittsburgh was listed among the “eleven most livable cities in the world” by Metropolis magazine. The Economist‘s Global Liveability Ranking placed Pittsburgh as the most or second-most livable city in the United States in 2005, 2009, 2011, 2012, 2014, and 2018. The region is a hub for Leadership in Energy and Environmental Design and energy extraction.

Pittsburgh was named in 1758, by General John Forbes, in honor of British statesman William Pitt, 1st Earl of Chatham. As Forbes was a Scotsman, he probably pronounced the name PITS-bər-ə (similar to Edinburgh).

Pittsburgh was incorporated as a borough on April 22, 1794, with the following Act:
“Be it enacted by the Pennsylvania State Senate and Pennsylvania House of Representatives of the Commonwealth of Pennsylvania … by the authority of the same, that the said town of Pittsburgh shall be … erected into a borough, which shall be called the borough of Pittsburgh for ever.”

From 1891 to 1911, the city’s name was federally recognized as “Pittsburg”, though use of the final h was retained during this period by the city government and other local organizations. After a public campaign, the federal decision to drop the h was reversed. The Pittsburg Press continued spelling the city without an h until 1921.

The area of the Ohio headwaters was long inhabited by the Shawnee and several other settled groups of Native Americans. Shannopin’s Town was an 18th-century Lenape (Delaware) town located roughly from where Penn Avenue is today, below the mouth of Two Mile Run, from 30th Street to 39th Street. According to George Croghan, the town was situated on the south bank of the Allegheny, nearly opposite what is now known as Herr’s Island, in what is now the Lawrenceville neighborhood.

The first known European to enter the region was the French explorer Robert de La Salle from Quebec during his 1669 expedition down the Ohio River.^{[better source needed]}European pioneers, primarily Dutch, followed in the early 18th century. Michael Bezallion was the first to describe the forks of the Ohio in a 1717 manuscript, and later that year European fur traders established area posts and settlements.

In 1749, French soldiers from Quebec launched an expedition to the forks to unite Canada with French Louisiana via the rivers. During 1753–1754, the British hastily built Fort Prince George before a larger French force drove them off. The French built Fort Duquesne based on LaSalle’s 1669 claims. The French and Indian War, the North American front of the Seven Years’ War, began with the future Pittsburgh as its center. British General Edward Braddock was dispatched with Major George Washington as his aide to take Fort Duquesne. The British and colonial force were defeated at Braddock’s Field. General John Forbes finally took the forks in 1758. He began construction on Fort Pitt, named after William Pitt the Elder, while the settlement was named “Pittsborough”.

During Pontiac’s War, a loose confederation of Native American tribes laid siege to Fort Pitt in 1763; the siege was eventually lifted after Colonel Henry Bouquet defeated a portion of the besieging force at the Battle of Bushy Run. Bouquet strengthened the defenses of Fort Pitt the next year.

During this period, the powerful nations of the Iroquois Confederacy, based in New York, had maintained control of much of the Ohio Valley as hunting grounds by right of conquest after defeating other tribes. By the terms of the 1768 Treaty of Fort Stanwix, the Penns were allowed to purchase the modern region from the Iroquois. A 1769 survey referenced the future city as the “Manor of Pittsburgh”. Both the Colony of Virginia and the Province of Pennsylvania claimed the region under their colonial charters until 1780, when they agreed under a federal initiative to extend the Mason–Dixon line westward, placing Pittsburgh in Pennsylvania. On March 8, 1771, Bedford County, Pennsylvania was created to govern the frontier.

On April 16, 1771, the city’s first civilian local government was created as Pitt Township. William Teagarden was the first constable, and William Troop was the first clerk.

Following the American Revolution, the village of Pittsburgh continued to grow. One of its earliest industries was boat building for settlers of the Ohio Country. In 1784, Thomas Viceroy completed a town plan which was approved by the Penn family attorney. Pittsburgh became a possession of Pennsylvania in 1785. The following year, the Pittsburgh Post-Gazette was started, and in 1787, the Pittsburgh Academy was chartered. Unrest during the Whiskey Rebellion of 1794 resulted in federal troops being sent to the area. By 1797, glass manufacture began, while the population grew to around 1,400. Settlers arrived after crossing the Appalachian Mountains or through the Great Lakes. Fort Pitt (now Pittsburgh) at the source of the Ohio River became the main base for settlers moving into the Northwest Territory.

The federal government recognizes Pittsburgh as the starting point for the Lewis and Clark Expedition. Preparations began in Pittsburgh in 1803 when Meriwether Lewis purchased a keelboat that would later be used to ascend the Missouri River.

The War of 1812 cut off the supply of British goods, stimulating American industry. By 1815, Pittsburgh was producing significant quantities of iron, brass, tin, and glass. On March 18, 1816, the 46-year-old local government became a city. It was served by numerous river steamboats, that increased trading traffic on the rivers.

In the 1830s, many Welsh people from the Merthyr steelworks immigrated to the city following the aftermath of the Merthyr Rising. By the 1840s, Pittsburgh was one of the largest cities west of the Allegheny Mountains. The Great Fire of Pittsburgh destroyed over a thousand buildings in 1845. The city rebuilt with the aid of Irish immigrants who came to escape the Great Famine. By 1857, Pittsburgh’s 1,000 factories were consuming 22 million coal bushels yearly. Coal mining and iron manufacturing attracted waves of European immigrants to the area, the most came from Germany.

Because Pennsylvania had been established as a free state after the Revolution, enslaved African Americans sought freedom here through escape as refugees from the South, or occasionally fleeing from travelers they were serving who stayed in the city. There were active stations of the Underground Railroad in the city, and numerous refugees were documented as getting help from station agents and African-American workers in city hotels. The Drennen Slave Girl walked out of the Monongahela House in 1850, apparently to freedom. The Merchant’s Hotel was also a place where African-American workers would advise slaves the state was free and aid them in getting to nearby stations of the Underground Railroad. Sometimes refugee slaves from the South stayed in Pittsburgh, but other times they continued North, including into Canada. Many slaves left the city and county for Canada after Congress passed the 1850 Fugitive Slave Act, as it required cooperation from law enforcement even in free states and increased penalties. From 1850 to 1860, the black population in Allegheny County dropped from 3,431 to 2,725 as people headed to more safety in Canada.

The American Civil War boosted the city’s economy with increased iron and armament demand by the Union. Andrew Carnegie began steel production in 1875 at the Edgar Thomson Steel Works in North Braddock, Pennsylvania, which evolved into the Carnegie Steel Company. He adopted the Bessemer process to increase production. Manufacturing was key to growth of Pittsburgh and the surrounding region. Railroad lines were built into the city along both rivers, increasing transportation access to important markets.

In 1901, J. P. Morgan and attorney Elbert H. Gary merged Carnegie Steel Company and several other companies into U.S. Steel. By 1910, Pittsburgh was the nation’s eighth-largest city, accounting for between one-third and one-half of national steel output.

The Pittsburgh Agreement was subscribed in May 1918 between the Czech and Slovak nationalities, as envisioned by T. G. Masaryk, concerning the future foundation of Czechoslovakia.

The city suffered severe flooding in March 1936.

The city’s population swelled to more than a half million, attracting numerous European immigrants to its industrial jobs. By 1940, non-Hispanic whites were 90.6% of the city’s population. Pittsburgh also became a main destination of the African-American Great Migration from the rural South during the first half of the 20th century. Limited initially by discrimination, some 95% percent of the men became unskilled steel workers.

During World War II, demand for steel increased and area mills operated 24 hours a day to produce 95 million tons of steel for the war effort. This resulted in the highest levels of air pollution in the city’s almost century of industry. The city’s reputation as the “arsenal of democracy” was being overshadowed by James Parton’s 1868 observation of Pittsburgh being “hell with the lid off.”

Following World War II, the city launched a clean air and civic revitalization project known as the “Renaissance,” cleaning up the air and the rivers. The “Renaissance II” project followed in 1977, focused on cultural and neighborhood development. The industrial base continued to expand through the 1970s, but beginning in the early 1980s both the area’s steel and electronics industries imploded during national industrial restructuring. There were massive layoffs from mill and plant closures.

In the later 20th century, the area shifted its economic base to education, tourism, and services, largely based on healthcare/medicine, finance, and high technology such as robotics. Although Pittsburgh successfully shifted its economy and remained viable, the city’s population has never rebounded to its industrial-era highs. While 680,000 people lived in the city proper in 1950, a combination of suburbanization and economic turbulence resulted in a decrease in city population, even as the metropolitan area population increased again.

During the late 2000s recession, Pittsburgh was economically strong, adding jobs when most cities were losing them. It was one of the few cities in the United States to see housing property values rise. Between 2006 and 2011, the Pittsburgh metropolitan statistical area (MSA) experienced over 10% appreciation in housing prices, the highest appreciation of the largest 25 metropolitan statistical areas in the United States, with 22 of the largest 25 metropolitan statistical areas experiencing depreciations in housing values.

In September 2009, the 2009 G20 Pittsburgh summit was held in Pittsburgh.

Pittsburgh has an area of 58.3 square miles (151 km), of which 55.6 square miles (144 km²) is land and 2.8 square miles (7.3 km), or 4.75%, is water. The 80th meridian west passes directly through the city’s downtown.

The city is on the Allegheny Plateau, within the ecoregion of the Western Allegheny Plateau. The Downtown area (also known as the Golden Triangle) sits where the Allegheny River flows from the northeast and the Monongahela River from the southeast to form the Ohio River. The convergence is at Point State Park and is referred to as “the Point.” The city extends east to include the Oakland and Shadyside sections, which are home to the University of Pittsburgh, Carnegie Mellon University, Chatham University, Carnegie Museum and Library, and many other educational, medical, and cultural institutions. The southern, western, and northern areas of the city are primarily residential.

Many Pittsburgh neighborhoods are steeply sloped with two-lane roads. More than a quarter of neighborhood names make reference to “hills,” “heights,” or similar features.

The steps of Pittsburgh consist of 800 sets of outdoor public stairways with 44,645 treads and 24,090 vertical feet. They include hundreds of streets composed entirely of stairs, and many other steep streets with stairs for sidewalks. Many provide vistas of the Pittsburgh area while attracting hikers and fitness walkers.

Bike and walking trails have been built to border many of the city’s rivers and hollows. The Great Allegheny Passage and Chesapeake and Ohio Canal Towpath connect the city directly to downtown Washington, D.C. (some 335 miles [539 km] away) with a continuous bike/running trail.

The city consists of the Downtown area, called the Golden Triangle, and four main areas surrounding it. These surrounding areas are subdivided into distinct neighborhoods (Pittsburgh has 90 neighborhoods). Relative to downtown, these areas are known as the Central, North Side/North Hills, South Side/South Hills, East End, and West End.

Downtown Pittsburgh has 30 skyscrapers, nine of which top 500 feet (150 m). The U.S. Steel Tower is the tallest, at 841 ft (256 m). The Cultural District consists of a 14-block area of downtown along the Allegheny River. This district contains many theaters and arts venues and is home to a growing residential segment. Most significantly, the Pittsburgh Cultural Trust is embarking on RiverParc, a four-block mixed-use “green” community, featuring 700 residential units and multiple towers of between 20 and 30 stories. The Firstside portion of Downtown borders the Monongahela River, the historic Mon Wharf and hosts the distinctive PPG Place Gothic-style glass skyscraper complex. New condo towers have been constructed and historic office towers are converted to residential use, increasing 24-hour residents. Downtown is served by the Port Authority’s light rail system and multiple bridges leading north and south. It is also home to Point Park University and Duquesne University which borders Uptown.

The North Side is home to various neighborhoods in transition. What is known today as Pittsburgh’s North Side was once known as Allegheny City, and operated as a city independently of Pittsburgh until it was merged with Pittsburgh in 1907 under great protest from its citizens. The North Side is primarily composed of residential neighborhoods and is noteworthy for its well-constructed and architecturally interesting homes. Many buildings date from the 19th century and are constructed of brick or stone and adorned with decorative woodwork, ceramic tile, slate roofs and stained glass. The North Side is also home to attractions such as Acrisure Stadium, PNC Park, Carnegie Science Center, National Aviary, Andy Warhol Museum, Mattress Factory art museum, Children’s Museum of Pittsburgh, Randyland, Penn Brewery, Allegheny Observatory, and Allegheny General Hospital.

The South Side was once the site of railyards and associated dense, inexpensive housing for mill and railroad workers. Since the late 20th century, the city undertook a Main Street program in cooperation with the National Trust for Historic Preservation, encouraging design and landscape improvements on East Carson Street, and supporting new retail. The area has become a local Pittsburgher destination, and the value of homes in the South Side had increased in value by about 10% annually for the 10 years up to 2014. East Carson Street has developed as one of the most vibrant areas of the city, packed with diverse shopping, ethnic eateries, vibrant nightlife, and live music venues.

In 1993 the Urban Redevelopment Authority of Pittsburgh purchased the South Side Works steel mill property. It collaborated with the community and various developers to create a master plan for a mixed-use development, to include a riverfront park, office space, housing, health-care facilities, and indoor practice fields for the Pittsburgh Steelers and Pitt Panthers. Construction began in 1998. The SouthSide Works has been open since 2005, featuring many stores, restaurants, offices, and the world headquarters for American Eagle Outfitters.

The East End of Pittsburgh is home to the University of Pittsburgh, Carnegie Mellon University, Carlow University, Chatham University, The Carnegie Institute’s Museums of Art and Natural History, Phipps Conservatory, and Soldiers and Sailors Memorial Hall. It is also home to many parks and public spaces including Mellon Park, Westinghouse Park, Schenley Park, Frick Park, The Frick Pittsburgh, Bakery Square, and the Pittsburgh Zoo and PPG Aquarium. The neighborhoods of Shadyside and Squirrel Hill are large, wealthy neighborhoods with some apartments and condos, and pedestrian-oriented shopping/business districts. Squirrel Hill is also known as the hub of Jewish life in Pittsburgh, home to approximately 20 synagogues. Oakland, heavily populated by undergraduate and graduate students, is home to most of the universities, and the Petersen Events Center. The Strip District to the west along the Allegheny River is an open-air marketplace by day and a clubbing destination by night. Bloomfield is Pittsburgh’s Little Italy and is known for its Italian restaurants and grocers. Lawrenceville is a revitalizing rowhouse neighborhood popular with artists and designers. The Hill District was home to photographer Charles Harris as well as various African-American jazz clubs. Other East End neighborhoods include Point Breeze, Regent Square, Highland Park, Homewood, Lincoln-Lemington-Belmar, Larimer, East Hills, East Liberty, Polish Hill, Hazelwood, Garfield, Morningside, and Stanton Heights.

The West End includes Mt. Washington, with its famous view of the Downtown skyline and numerous other residential neighborhoods such as Sheraden and Elliott.

Many of Pittsburgh’s patchwork of neighborhoods still retain ethnic characters reflecting the city’s settlement history. These include:

Several neighborhoods on the edges of the city are less urban, featuring tree-lined streets, yards and garages, with a more suburban character. Oakland, the South Side, the North Side, and the Golden Triangle are characterized by more density of housing, walking neighborhoods, and a more diverse, urban feel.

Pittsburgh falls within the borders of the Northeastern United States as defined by multiple US Government agencies. Pittsburgh is the principal city of the Pittsburgh Combined Statistical Area, a Combined statistical area defined by the U.S. Census Bureau.

Pittsburgh falls within the borders of Appalachia as defined by the Appalachian Regional Commission, and has long been characterized as the “northern urban industrial anchor of Appalachia.” In its post-industrial state, Pittsburgh has been characterized as the “Paris of Appalachia”, recognizing the city’s cultural, educational, healthcare, and technological resources, and is the largest city in Appalachia.

Under the Köppen climate classification, Pittsburgh falls within either a hot-summer humid continental climate (Dfa) if the 0 °C (32 °F) isotherm is used or a humid subtropical climate (Cfa) if the −3 °C (27 °F) isotherm is used. Summers are hot and winters are moderately cold with wide variations in temperature. Despite this, it has one of the most pleasant summer climates between medium and large cities in the U.S. The city and river valleys lie in the USDA plant hardiness zone 6b while higher elevated areas and some suburbs lie in zone 6a. The area has four distinct seasons: winters are cold and snowy, springs and falls are mild with moderate levels of sunshine, and summers are warm. As measured by percent possible sunshine, summer is by far the sunniest season.

The warmest month of the year in Pittsburgh is July, with a 24-hour average of 73.2 °F (22.9 °C). Conditions are often humid, and combined with highs reaching 90 °F (32 °C) on an average 9.5 days a year, a considerable heat index arises. The coolest month is January, when the 24-hour average is 28.8 °F (−1.8 °C), and lows of 0 °F (−18 °C) or below can be expected on an average 2.6 nights per year. Officially, record temperatures range from −22 °F (−30 °C), on January 19, 1994 to 103 °F (39 °C), which occurred three times, most recently on July 16, 1988; the record cold daily maximum is −3 °F (−19 °C), which occurred three times, most recently the day of the all-time record low, while, conversely, the record warm daily minimum is 82 °F (28 °C) on July 1, 1901. Due to elevation and location on the windward side of the Appalachian Mountains, 100 °F (38 °C)+ readings are very rare, and were last seen on July 15, 1995.

Average annual precipitation is 39.61 inches (1,006 mm) and precipitation is greatest in May while least in October; annual precipitation has historically ranged from 22.65 in (575 mm) in 1930 to 57.83 in (1,469 mm) in 2018. On average, December and January have the greatest number of precipitation days. Snowfall averages 44.1 inches (112 cm) per season, but has historically ranged from 8.8 in (22 cm) in 1918–19 to 80 in (200 cm) in 1950–51. There is an average of 59 clear days and 103 partly cloudy days per year, while 203 days are cloudy. In terms of annual percent-average possible sunshine received, Pittsburgh (45%) is similar to Seattle (49%).

In 2019, the “State of the Air” report from the American Lung Association (ALA) found that air quality in the Pittsburgh-New Castle-Weirton, PA-OH-WV metro area worsened, not only for ozone (smog), but also for the second year in a row for both the daily and long-term measures of fine particle pollution. Outside of California, Allegheny County is the only county in the United States that recorded failing grades for all three.

In a 2013 ranking of 277 metropolitan areas in the United States, the American Lung Association ranked only six U.S. metro areas as having higher amounts of short-term particle pollution, and only seven U.S. metro areas having higher amounts of year-round particle pollution than Pittsburgh. For ozone (smog) pollution, Pittsburgh was ranked 24th among U.S. metro areas. The area has improved its air quality with every annual survey. The ALA’s rankings have been disputed by the Allegheny County Health Department (ACHD), since data from only the worst of the region’s 20 air quality monitors is considered by the ALA, without any context or averaging. The lone monitor used is immediately downwind and adjacent to U.S. Steel’s Clairton Coke Works, the nation’s largest coke mill, and several municipalities outside the city’s jurisdiction of pollution controls, leading to possible confusion that Pittsburgh is the source or center of the emissions cited in the survey. The region’s readings also reflect pollution swept in from Ohio and West Virginia.

Although the county was still below the “pass” threshold, the report showed substantial improvement over previous decades on every air quality measure. Fewer than 15 high ozone days were reported between 2007 and 2009, and just 10 between 2008 and 2010, compared to more than 40 between 1997 and 1999. ACHD spokesman Guillermo Cole stated “It’s the best it’s been in the lifetime for virtually every resident in this county … We’ve seen a steady decrease in pollution levels over the past decade and certainly over the past 20, 30, 40, 50 years, or more.”

In the summer of 2017, a crowd sourced air quality monitoring application, Smell PGH, was launched. As air quality is still a concern of many in the area, the app allows for users to report odd smells and informs local authorities.

The city contains 31,000 trees on 900 miles of streets, by the last count conducted in 2005. A 2011 analysis of Pittsburgh’s tree cover, which involved sampling more than 200 small plots throughout the city, showed a value of between $10 and $13 million in annual benefits based on the urban forest contributions to aesthetics, energy use and air quality. Energy savings from shade, impact on city air and water quality, and the boost in property values were taken into account in the analysis. The city spends $850,000 annually on street tree planting and maintenance.

The local rivers continue to have pollution levels exceeding EPA limits. This is caused by frequently overflowing untreated sewage into local waterways, due to flood conditions and antiquated infrastructure. Pittsburgh has a combined sewer system, where its sewage pipes contain both stormwater and wastewater. The pipes were constructed in the early 1900s, and the sewage treatment plant was built in 1959. Due to insufficient improvements over time, the city is faced with public health concerns regarding its water. As little as a tenth of an inch of rain causes runoffs from the sewage system to drain into local rivers. Nine billion gallons of untreated waste and stormwater flow into rivers, leading to health hazards and Clean Water Act violations. The local sewage authority, Allegheny County Sanitary Authority, or ALCOSAN, is operating under Consent Decree from the EPA to come up with solutions. In 2017, ALCOSAN proposed a $2 billion upgrade to the system which is moving closer to EPA approval.

Pittsburgh Water and Sewer Authority (PWSA) is the city’s agency required to replace pipes and charge water rates. They have come under fire from both city and state authorities due to alleged mismanagement. In 2017, Mayor William Peduto advocated for a restructuring of the PWSA and a partially privatized water authority. Governor Wolf subsequently assigned the PWSA to be under the oversight of the Public Utilities Commission (PUC).

At the 2010 census, there were 305,704 people residing in Pittsburgh, a decrease of 8.6% since 2000; 66.0% of the population was White, 25.8% Black or African American, 0.2% American Indian and Alaska Native, 4.4% Asian, 0.3% Other, and 2.3% mixed; in 2020, 2.3% of Pittsburgh’s population was of Hispanic or Latino American origin of any race. Non-Hispanic whites were 64.8% of the population in 2010, compared to 78.7% in 1970. By the 2020 census, the population slightly declined further to 302,971. Its racial and ethnic makeup in 2020 was 64.7% non-Hispanic white, 23.0% Black or African American, 5.8% Asian, and 3.2% Hispanic or Latino American of any race.

Since the beginning of the 21st century, the five largest European ethnic groups in Pittsburgh were German (19.7%), Irish (15.8%), Italian (11.8%), Polish (8.4%), and English (4.6%), while the metropolitan area is approximately 22% German-American, 15.4% Italian American and 11.6% Irish American. Pittsburgh has one of the largest Italian-American communities in the nation, and the fifth-largest Ukrainian community per the 1990 census. Pittsburgh has one of the most extensive Croatian communities in the United States. Overall, the Pittsburgh metro area has one of the largest populations of Slavic Americans in the country.

Pittsburgh has a sizable Black and African American population, concentrated in various neighborhoods especially in the East End. There is also a small Asian community consisting of Indian immigrants, and a small Hispanic community consisting of Mexicans and Puerto Ricans.

According to a 2010 Association of Religion Data Archives (ARDA) study, residents include 773,341 “Catholics”; 326,125 “Mainline Protestants”; 174,119 “Evangelical Protestants;” 20,976 “Black Protestants;” and 16,405 “Orthodox Christians,” with 996,826 listed as “unclaimed” and 16,405 as “other” in the metro area. A 2017 study by the Cohen Center for Modern Jewish Studies at Brandeis University estimated the Jewish population of Greater Pittsburgh was 49,200.

According to a 2014 study by the Pew Research Center, 78% of the population of the city identified themselves as Christians, with 42% professing attendance at a variety of churches that could be considered Protestant, and 32% professing Catholic beliefs. while 18% claim no religious affiliation. The same study says that other religions (including Judaism, Buddhism, Islam, and Hinduism) collectively make up about 4% of the population.

In 2010, there were 143,739 households, out of which 21.9% had children under the age of 18 living with them, 31.2% were married couples living together, 16.5% had a female householder with no husband present, and 48.4% were non-families. 39.4% of all households were made up of individuals, and 13.7% had someone living alone who was 65 years of age or older. The average household size was 2.17 and the average family size was 2.95.

In the city, the population was spread out, with 19.9% under the age of 18, 14.8% from 18 to 24, 28.6% from 25 to 44, 20.3% from 45 to 64, and 16.4% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 90.7 males. For every 100 females age 18 and over, there were 87.8 males.

The median income for a household in the city was $28,588, and the median income for a family was $38,795. Males had a median income of $32,128 versus $25,500 for females. The per capita income for the city was $18,816. About 15.0% of families and 20.4% of the population were below the poverty line, including 27.5% of those under the age of 18 and 13.5% ages 65 or older. By the 2019 American Community Survey, the median income for a household increased to $53,799. Families had a median income of $68,922; married-couple families had a median income of $93,500; and non-family households had a median income of $34,448. Pittsburgh’s wealthiest suburbs within city limits are Squirrel Hill and Point Breeze, the only two areas of the city which have average household incomes over $100,000 a year. Outside of city limits, Sewickley Heights is by a wide margin the wealthiest suburb of Pittsburgh within Allegheny County, with an average yearly household income of just over $218,000. Sewickely Heights is seen as one of Pittsburgh’s wealthiest suburbs culturally as well, titles which the suburbs of Upper St. Clair, Fox Chapel, Wexford, and Warrendale also have been bestowed.

In a 2002 study, Pittsburgh ranked 22nd of 69 urban places in the U.S. in the number of residents 25 years or older who had completed a bachelor’s degree, at 31%. Pittsburgh ranked 15th of the 69 places in the number of residents 25 years or older who completed a high school degree, at 84.7%.

The metro area has shown greater residential racial integration during the last 30 years. The 2010 census ranked 18 other U.S. metros as having greater black-white segregation, while 32 other U.S. metros rank higher for black-white isolation.

As of 2018, much of Pittsburgh’s population density was concentrated in the central, southern, and eastern areas. The city limits itself have a population density of 5,513 people per square mile; its most densely populated parts are North Oakland (at 21,200 per square mile) and Uptown Pittsburgh (at 19,869 per square mile). Outside of the city limits, Dormont and Mount Oliver are Pittsburgh’s most densely-populated neighborhoods, with 11,167 and 9,902 people per square mile respectively.

Pittsburgh has adapted since the collapse of its century-long steel and electronics industries. The region has shifted to high technology, robotics, health care, nuclear engineering, tourism, biomedical technology, finance, education, and services. Annual payroll of the region’s technology industries, when taken in aggregate, exceeded $10.8 billion in 2007, and in 2010 there were 1,600 technology companies. A National Bureau of Economic Research 2014 report named Pittsburgh the second-best U.S. city for intergenerational economic mobility or the American Dream. Reflecting the citywide shift from industry to technology, former factories have been renovated as modern office space. Google has research and technology offices in a refurbished 1918–1998 Nabisco factory, a complex known as Bakery Square. Some of the factory’s original equipment, such as a large dough mixer, were left standing in homage to the site’s industrial roots. Pittsburgh’s transition from its industrial heritage has earned it praise as “the poster child for managing industrial transition”. Other major cities in the northeast and mid-west have increasingly borrowed from Pittsburgh’s model in order to renew their industries and economic base.

The largest employer in the city is the University of Pittsburgh Medical Center, with 48,000 employees. All hospitals, outpatient clinics, and doctor’s office positions combine for 116,000 jobs, approximately 10% of the jobs in the region. An analyst recently observed of the city’s medical sector: “That’s both more jobs and a higher share of the region’s total employment than the steel industry represented in the 1970s.”