Boston (US: /ˈbɔːstən/, UK: /ˈbɒstən/),[5] officially the City of Boston, is the capital and most populous city of the Commonwealth of Massachusetts in the United States and 24th-most populous city in the country.[6] The city proper covers 48.4 square miles (125 km2)[7] with a population of 675,647 in 2020,[2] also making it the most populous city in New England.[8] It is the seat of Suffolk County (although the county government was disbanded on July 1, 1999).[9] The city is the economic and cultural anchor of a substantially larger metropolitan area known as Greater Boston, a metropolitan statistical area (MSA) home to a census-estimated 4.8 million people in 2016 and ranking as the tenth-largest MSA in the country.[10] A broader combined statistical area (CSA), generally corresponding to the commuting area[11] and including Providence, Rhode Island, is home to some 8.2 million people, making it the sixth most populous in the United States.[12]

Boston is one of the oldest municipalities in the United States, founded on the Shawmut Peninsula in 1630 by Puritan settlers from the English town of the same name.[13][14] It was the scene of several key events of the American Revolution, such as the Boston Massacre, the Boston Tea Party, the Battle of Bunker Hill and the siege of Boston. Upon American independence from Great Britain, the city continued to be an important port and manufacturing hub as well as a center for education and culture.[15][16] The city has expanded beyond the original peninsula through land reclamation and municipal annexation. Its rich history attracts many tourists, with Faneuil Hall alone drawing more than 20 million visitors per year.[17] Boston's many firsts include the United States' first public park (Boston Common, 1634), first public or state school (Boston Latin School, 1635)[18] and first subway system (Tremont Street subway, 1897).[19]

Today, Boston is a thriving center of scientific research. The Boston area's many colleges and universities make it a world leader in higher education,[20] including law, medicine, engineering and business, and the city is considered to be a global pioneer in innovation and entrepreneurship, with nearly 5,000 startups.[21][22][23] Boston's economic base also includes finance,[24] professional and business services, biotechnology, information technology and government activities.[25] Households in the city claim the highest average rate of philanthropy in the United States;[26] businesses and institutions rank among the top in the country for environmental sustainability and investment.[27] The city has one of the highest costs of living in the United States[28][29] as it has undergone gentrification.[

Chicago (/ʃɪˈkɑːɡoʊ/ ( listen), locally also /-ˈkɔː-/), officially the City of Chicago, located on the shores of freshwater Lake Michigan, is the third most populous city in America after New York and Los Angeles. As of the 2017 census-estimate, Chicago has a population of 2,716,450, which makes it the most populous city in both the state of Illinois and the Midwestern United States. It is the county seat of Cook County, the second most populous county in the U.S. Chicago is the principal city of the Chicago metropolitan area, which is often referred to as "Chicagoland." The Chicago metropolitan area has nearly 10 million people, is the third-largest in the United States, the fourth largest in North America, and the third largest metropolitan area in the world by land area. Chicago is the birthplace of the skyscraper, and considered the most influential architectural city of the 20th century.[6] In finance, the city saw the creation of the first standardized futures contracts at the Chicago Board of Trade; which today is the largest and most diverse derivatives market in the world, generating 20% of all volume in commodities and financial futures.[7]

Chicago was incorporated as a city in 1837 near a portage between the Great Lakes and the Mississippi River watershed and grew rapidly in the mid-nineteenth century.[8] After the Great Chicago Fire of 1871, which destroyed several square miles and left more than 100,000 homeless, the city made a concerted effort to rebuild.[9] The construction boom accelerated population growth throughout the following decades, and by 1900 Chicago was one of the five largest cities in the world.[10] During this period, Chicago made noted contributions to urban planning and zoning standards, which included creating new construction styles (including the Chicago School of architecture), the development of the City Beautiful Movement, and the steel-framed skyscraper.[11]

Positioned along Lake Michigan, the city is an international hub for finance, commerce, industry, technology, telecommunications, and transportation. O'Hare International Airport is the one of the busiest airports in the world, and the region also has the largest number of U.S. highways and railroad freight.[12] In 2012, Chicago was listed as an alpha global city by the Globalization and World Cities Research Network,[13] and it ranked seventh in the entire world in the 2017 Global Cities Index.[14] Chicago has the fourth-largest gross metropolitan product in the world — generating about $670.5 billion according to September 2017 estimates — ranking it after the metropolitan areas of Tokyo, New York City, and Los Angeles, and ranking ahead of number five London and number six Paris.[15] Chicago has one of the world's largest and most diversified and balanced economies, not being dependent on any one industry, with no single industry employing more than 14% of the workforce.[16]

Chicago was the second most visited city in the United States with 55 million domestic and international visitors,[17][18] not far behind the 62 million visitors to New York City in 2017.[19] The city ranked first place in the 2018 Time Out City Life Index, a global quality of life survey of 15,000 people in 32 cities.[20][21][22][23][24] Landmarks in the city include Millennium Park, Navy Pier, the Magnificent Mile, the Art Institute of Chicago, Museum Campus, the Willis (Sears) Tower, the Museum of Science and Industry, and Lincoln Park Zoo. Chicago's culture includes the visual arts, literature, film, theater, comedy (especially improvisational comedy), food, and music, particularly jazz, blues, soul, hip-hop, gospel,[25] and electronic dance music including house music. There are many colleges and universities in the Chicago area, of which the University of Chicago, Northwestern University, and the University of Illinois at Chicago are classified as "highest research" doctoral universities.

Chicago has professional sports teams in each of the major professional leagues, including two Major League Baseball teams. The city has had several nicknames throughout its history such as the Windy City, Chi-Town, Second City, and the City of the Big Shoulders, referring to its numerous towers and skyscrapers.[26]

Dallas (/ˈdæləs/) is a city in the U.S. state of Texas and the largest city in and seat of Dallas County, with portions extending into Collin, Denton, Kaufman and Rockwall counties. With a 2020 census population of 1,304,379,[3] it is the ninth most-populous city in the U.S.[10] and the third-largest in Texas after Houston and San Antonio.[11] Located in North Texas, the city of Dallas is the main core of the largest metropolitan area in the Southern United States and the largest inland metropolitan area in the U.S. that lacks any navigable link to the sea.[a] It is the most populous city in the Dallas–Fort Worth metroplex, the fourth-largest metropolitan area in the country at 7.5 million people.[12]

Dallas and nearby Fort Worth were initially developed due to the construction of major railroad lines through the area allowing access to cotton, cattle and later oil in North and East Texas. The construction of the Interstate Highway System reinforced Dallas's prominence as a transportation hub, with four major interstate highways converging in the city and a fifth interstate loop around it. Dallas then developed as a strong industrial and financial center and a major inland port, due to the convergence of major railroad lines, interstate highways and the construction of Dallas/Fort Worth International Airport, one of the largest and busiest airports in the world.[13] In addition, Dallas has DART (Dallas Area Rapid Transit) with different colored train lines that transport throughout the Metroplex.[14]

Dominant sectors of its diverse economy include defense, financial services, information technology, telecommunications, and transportation.[15] Dallas is home to nine Fortune 500 companies within the city limits[16] while the Dallas–Fort Worth metroplex hosts twenty-two Fortune 500 companies, the second most in Texas and fourth most in the United States.[17][18] Over 41 colleges and universities are located within its metropolitan area, which is the most of any metropolitan area in Texas. The city has a population from a myriad of ethnic and religious backgrounds and one of the largest LGBT communities in the U.S.[19][20] WalletHub named Dallas the fifth most diverse city in the United States in 2018.

Dublin (/ˈdʌblɪn/; Irish: Baile Átha Cliath,[12] pronounced [ˈbˠalʲə aːhə ˈclʲiə] or [ˌbʲlʲaː ˈclʲiə]) is the capital and largest city of Ireland.[13][14] Situated on a bay on the east coast, at the mouth of the River Liffey, it is in the province of Leinster and the Eastern and Midland Region. It is bordered on the south by the Dublin Mountains, a part of the Wicklow Mountains range. At the 2016 census, it had an urban area population of 1,173,179,[8] while the population of the traditional County Dublin as a whole was 1,347,359.[15] The population of the Greater Dublin Area was 1,904,806.[16]

There is archaeological debate regarding precisely where and when Dublin originated, with a settlement established by the Gaels during or before the 7th century CE,[17] and a second, Viking, settlement, following. As the small Kingdom of Dublin, the city grew, and it became Ireland's principal settlement following the Norman invasion.[17] The city expanded rapidly from the 17th century and was briefly the second largest city in the British Empire after the Acts of Union in 1800. Following independence in 1922, Dublin became the capital of the Irish Free State, later renamed Ireland in 1937.

Dublin is a contemporary and historical centre for Irish education, arts and culture, administration and industry. As of 2018 the city was listed by the Globalization and World Cities Research Network (GaWC) as a global city, with a ranking of "Alpha minus", which places it as one of the top thirty cities in the world.

The name Dublin derives from the Irish word Dubhlinn, early Classical Irish Dubhlind/Duibhlind, from dubh ([d̪uβ], [d̪uw], [d̪uː]) meaning "black, dark", and lind ([lʲiɲ(d̪ʲ)]) "pool", referring to a dark tidal pool. This tidal pool was located where the River Poddle entered the Liffey, on the site of the castle gardens at the rear of Dublin Castle. In Modern Irish the name is Duibhlinn, and Irish rhymes from County Dublin show that in Dublin Leinster Irish it was pronounced Duílinn [ˈd̪ˠiːlʲiɲ]. The original pronunciation is preserved in the names for the city in other languages such as Old English Difelin, Old Norse Dyflin, modern Icelandic Dyflinn and modern Manx Divlyn as well as Welsh Dulyn and Breton Dulenn. Other localities in Ireland also bear the name Duibhlinn, variously anglicised as Devlin,[20] Divlin[21] and Difflin.[22] Historically, scribes using the Gaelic script wrote bh with a dot over the b, rendering Duḃlinn or Duiḃlinn. Those without knowledge of Irish omitted the dot, spelling the name as Dublin. Variations on the name are also found in traditionally Gaelic-speaking areas of Scotland (Gàidhealtachd, cognate with Irish Gaeltacht), such as An Linne Dhubh ("the black pool"), which is part of Loch Linnhe.

It is now thought that the Viking settlement was preceded by a Christian ecclesiastical settlement known as Duibhlinn, from which Dyflin took its name.[23] Beginning in the 9th and 10th century, there were two settlements where the modern city stands. The Viking settlement of about 841, Dyflin, and a Gaelic settlement, Áth Cliath ("ford of hurdles")[24] further up river, at the present day Father Mathew Bridge (also known as Dublin Bridge), at the bottom of Church Street. Baile Átha Cliath, meaning "town of the hurdled ford", is the common name for the city in modern Irish. Áth Cliath is a place name referring to a fording point of the River Liffey near Father Mathew Bridge. Baile Átha Cliath was an early Christian monastery, believed to have been in the area of Aungier Street, currently occupied by Whitefriar Street Carmelite Church. There are other towns of the same name, such as Àth Cliath in East Ayrshire, Scotland, which is anglicised as Hurlford.

Houston (/ˈhjuːstən/ ( listen) HEW-stən) is the most populous city in the U.S. state of Texas and the fourth most populous city in the United States, with a census-estimated population of 2.312 million in 2017.[7] It is the most populous city in the Southern United States[8] and on the Gulf Coast of the United States. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, it is the seat of Harris County and the principal city of the Greater Houston metropolitan area, which is the fifth most populous MSA in the United States and the second most populous in Texas after the Dallas–Fort Worth metroplex. With a land area of 599.59 square miles (1,552.9 km2),[7] Houston is the ninth most expansive city in the United States.

Houston was founded by land speculators on August 30, 1836,[9] at the confluence of Buffalo Bayou and White Oak Bayou (a point now known as Allen's Landing)[10] and incorporated as a city on June 5, 1837.[11] The city is named after former General Sam Houston, who was president of the Republic of Texas and had won Texas' independence from Mexico at the Battle of San Jacinto 25 miles (40 km) east of Allen's Landing.[11] After briefly serving as the capital of the Republic in the late 1830s, Houston grew steadily into a regional trading center for the remainder of the 19th century.[9]

The arrival of the 20th century saw a convergence of economic factors which fueled rapid growth in Houston, including a burgeoning port and railroad industry, the decline of Galveston as Texas' primary port following a devastating 1900 hurricane, the subsequent construction of the Houston Ship Channel, and the Texas oil boom.[9] In the mid-20th century, Houston's economy diversified as it became home to the Texas Medical Center—the world's largest concentration of healthcare and research institutions—and NASA's Johnson Space Center, where the Mission Control Center is located.

Houston's economy has a broad industrial base in energy, manufacturing, aeronautics, and transportation. Leading in health care sectors and building oilfield equipment, Houston has the second most Fortune 500 headquarters of any U.S. municipality within its city limits (after New York City).[12][13] The Port of Houston ranks first in the United States in international waterborne tonnage handled and second in total cargo tonnage handled.[14] Nicknamed the "Space City", Houston is a global city, with strengths in culture, medicine, and research. The city has a population from various ethnic and religious backgrounds and a large and growing international community. Houston is the most diverse metropolitan area in Texas and has been described as the most racially and ethnically diverse major metropolis in the U.S.[15] It is home to many cultural institutions and exhibits, which attract more than 7 million visitors a year to the Museum District. Houston has an active visual and performing arts scene in the Theater District and offers year-round resident companies in all major performing arts.[16]

London (/ˈlʌndən/ ( listen) LUN-dən) is the capital and most populous city of England and the United Kingdom.[8][9] Standing on the River Thames in the south east of the island of Great Britain, London has been a major settlement for two millennia. It was founded by the Romans, who named it Londinium.[10] London's ancient core, the City of London, largely retains its 1.12-square-mile (2.9 km2) medieval boundaries. Since at least the 19th century, "London" has also referred to the metropolis around this core, historically split between Middlesex, Essex, Surrey, Kent and Hertfordshire,[11][12][13] which today largely makes up Greater London,[14][15][note 1] a region governed by the Mayor of London and the London Assembly.[16][note 2][17]

London is one of the leading global cities[18][19] in the arts, commerce, education, entertainment, fashion, finance, healthcare, media, professional services, research and development, tourism and transportation.[20][21][22] It is the world's largest financial centre[23][24][25][26] and has the fifth or sixth largest metropolitan area GDP in the world.[note 3][27][28] London is often regarded as a world cultural capital.[29][30][31] It is the world's most-visited city as measured by international arrivals[32] and has the world's largest city airport system measured by passenger traffic.[33] It is the world's leading investment destination,[34][35][36][37] hosting more international retailers[38][39] and ultra high-net-worth individuals[40][41] than any other city. London's universities form the largest concentration of higher education institutes in Europe.[42] In 2012, London became the first city to have hosted the modern Summer Olympic Games three times.[43]

London has a diverse range of people and cultures, and more than 300 languages are spoken in the region.[44] Its estimated mid-2016 municipal population (corresponding to Greater London) was 8,787,892,[4] the largest of any city in the European Union[45] and accounting for 13.4% of the UK population.[46] London's urban area is the second most populous in the EU, after Paris, with 9,787,426 inhabitants at the 2011 census.[47] The city's metropolitan area is the most populous in the EU with 14,040,163 inhabitants in 2016,[note 4][3] while the Greater London Authority states the population of the city-region (covering a large part of the south east) as 22.7 million.[48][49] London was the world's most populous city from around 1831 to 1925.[50]

London contains four World Heritage Sites: the Tower of London; Kew Gardens; the site comprising the Palace of Westminster, Westminster Abbey, and St Margaret's Church; and the historic settlement of Greenwich (in which the Royal Observatory, Greenwich defines the Prime Meridian, 0° longitude, and GMT).[51] Other landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge, Trafalgar Square and The Shard. London is home to numerous museums, galleries, libraries, sporting events and other cultural institutions, including the British Museum, National Gallery, Natural History Museum, Tate Modern, British Library and West End theatres.[52] The London Underground is the oldest underground railway network in the world.

Los Angeles (US: /lɔːs ˈændʒələs/ ( listen);[16][a] Spanish for "The Angels"; Spanish: Los Ángeles; Spanish: [los ˈaŋxeles]; officially the City of Los Angeles, known colloquially by its initials L.A.) is the second-most populous city in the United States, after New York City, and the most populous city in the Western United States. With an estimated population of four million,[17] Los Angeles is the largest and most populous city in the state of California and the cultural, financial, and commercial center of Southern California. Nicknamed the "City of Angels" partly because of its name's Spanish meaning, Los Angeles is known for its Mediterranean climate, ethnic diversity, and sprawling metropolis.

Los Angeles is located in a large basin bounded by the Pacific Ocean on one side and by mountains as high as 10,000 feet (3,000 m) on the others. The city proper, which covers about 469 square miles (1,210 km2),[18] is the seat of Los Angeles County, the most populated county in the country. Los Angeles is the principal city of the Los Angeles metropolitan area; with a population of 13.1 million residents it is the second largest in the United States after that of New York City.[19] It is part of the Los Angeles-Long Beach combined statistical area, also the second most populous in the nation with a 2015 estimated population of 18.7 million.[20]

Los Angeles is one of the most substantial economic engines within the United States, with a diverse economy in a broad range of professional and cultural fields. Los Angeles is also famous as the home of Hollywood, a major center of the world entertainment industry. A global city, it has been ranked 6th in the Global Cities Index and 9th in the Global Economic Power Index. The Los Angeles combined statistical area also has a gross metropolitan product of $831 billion (as of 2008), making it the third-largest in the world, after the Tokyo and New York metropolitan areas. Los Angeles hosted the 1932 and 1984 Summer Olympics and will host the event for a third time in 2028. The city also hosted the Miss Universe pageant twice, in 1990 and 2006.

Historically home to the Chumash and Tongva, Los Angeles was claimed by Juan Rodríguez Cabrillo for Spain in 1542 along with the rest of what would become Alta California. The city was officially founded on September 4, 1781, by Spanish governor Felipe de Neve. It became a part of Mexico in 1821 following the Mexican War of Independence. In 1848, at the end of the Mexican–American War, Los Angeles and the rest of California were purchased as part of the Treaty of Guadalupe Hidalgo, becoming part of the United States. Los Angeles was incorporated as a municipality on April 4, 1850, five months before California achieved statehood. The discovery of oil in the 1890s brought rapid growth to the city.[21] The completion of the Los Angeles Aqueduct in 1913, delivering water from Eastern California, later assured the city's continued rapid growth.

Miami (/maɪˈæmi/), officially the City of Miami, is a coastal metropolis located in Miami-Dade County in southeastern Florida (United States). With a population of 467,963 as of the 2020 census,[10] it is the 44th-largest city in the United States and the core of the nation's eighth-largest metropolitan area.[6] The city has the third-largest skyline in the U.S. with over 300 high-rises,[11] 58 of which exceed 491 ft (150 m).[12]

Miami is a major center and leader in finance, commerce, culture, arts, and international trade.[13][14] The metro area is by far the largest urban economy in Florida and the 12th largest in the United States, with a GDP of $344.9 billion as of 2017.[15] In 2020, Miami was classified as a Beta + level global city by the GaWC.[16] In 2019, Miami ranked seventh in the United States and 31st among global cities in business activity, human capital, information exchange, cultural experience, and political engagement.[17] According to a 2018 UBS study of 77 world cities, the city was ranked as the third-richest in the world and the second-richest in the United States in purchasing power.[18] Miami is one of the largest majority-minority cities in the United States and the fourth-largest majority-Hispanic city in the United States, with 70.2% of its population being Hispanic in 2020.[19]

Greater Downtown Miami has one of the largest concentrations of international banks in the United States, and is home to many large national and international companies.[20] The Health District, home to Jackson Memorial Hospital and the Leonard M. Miller School of Medicine at the University of Miami among others, is a major center for hospitals, clinics, and the biotechnology and medical research industries. PortMiami is the busiest cruise port in the world in both passenger traffic and cruise lines, and refers to itself as the "Cruise Capital of the World".[21] Miami is also a major tourism hub for international visitors, ranking second in the country after New York City.[22] Miami has been called the Gateway to Latin America.

New York, often called New York City (NYC) to distinguish it from the State of New York, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over 300.46 square miles (778.2 km²), New York City is also the most densely populated major city in the United States. Located at the southern tip of the state of New York, the city is the center of the New York metropolitan area, the largest metropolitan area in the world by urban landmass.^[9] With over 20.1 million people in its metropolitan statistical area and 23.5 million in its combined statistical area as of 2020, New York is one of the world's most populous megacities. New York City is a global cultural, financial, and media center with a significant influence on commerce, entertainment, research, technology, education, politics, tourism, dining, art, fashion, and sports. It is the most photographed city in the world.^[10] Home to the headquarters of the United Nations, New York is an important center for international diplomacy,^[11][12] an established safe haven for global investors,^[13] and is sometimes described as the capital of the world.

Situated on one of the world's largest natural harbors, with water covering 36.4% of its surface area, New York City is composed of five boroughs, each of which is coextensive with a respective county of the state of New York. The five boroughs—Brooklyn (Kings County), Queens (Queens County), Manhattan (New York County), the Bronx (Bronx County), and Staten Island (Richmond County)—were created when local governments were consolidated into a single municipal entity in 1898.^[14] The city and its metropolitan area constitute the premier gateway for legal immigration to the United States. As many as 800 languages are spoken in New York,^[15] making it the most linguistically diverse city in the world. New York is home to more than 3.2 million residents born outside the United States, the largest foreign-born population of any city in the world as of 2016.^[16][17] As of 2018, the New York metropolitan area is estimated to produce a gross metropolitan product (GMP) of nearly $1.8 trillion, ranking it first in the United States. If the New York metropolitan area were a sovereign state, it would have the eighth-largest economy in the world. New York is home to the highest number of billionaires of any city in the world.^[18]

New York City traces its origins to a trading post founded on the southern tip of Manhattan Island by Dutch colonists in approximately 1624. The settlement was named New Amsterdam (Dutch: Nieuw Amsterdam) in 1626 and was chartered as a city in 1653. The city came under English control in 1664 and was renamed New York after King Charles II of England granted the lands to his brother, the Duke of York.^[19][20] The city was regained by the Dutch in July 1673 and was renamed New Orange for one year and three months; the city has been continuously named New York since November 1674. New York City was the capital of the United States from 1785 until 1790,^[21] and has been the largest U.S. city since 1790. The Statue of Liberty greeted millions of immigrants as they came to the U.S. by ship in the late 19th and early 20th centuries, and is a symbol of the U.S. and its ideals of liberty and peace.^[22] In the 21st century, New York has emerged as a global node of creativity, entrepreneurship,^[23] and environmental sustainability,^[24][25] and as a symbol of freedom and cultural diversity.^[26] In 2019, New York was voted the greatest city in the world per a survey of over 30,000 people from 48 cities worldwide, citing its cultural diversity.^[27]

Many districts and monuments in New York City are major landmarks, including three of the world's ten most visited tourist attractions in 2013.^[28] A record 66.6 million tourists visited New York City in 2019. Times Square is the brightly illuminated hub of the Broadway Theater District,^[29] one of the world's busiest pedestrian intersections,^[28][30] and a major center of the world's entertainment industry.^[31] Many of the city's landmarks, skyscrapers, and parks are known around the world, as is the city's fast pace, spawning the term New York minute. The Empire State Building has become the global standard of reference to describe the height and length of other structures.^[32] Manhattan's real estate market is among the most expensive in the world.^[33][34] Providing continuous 24/7 service and contributing to the nickname The City That Never Sleeps, the New York City Subway is the largest single-operator rapid transit system worldwide, with 472 passenger rail stations. The city has over 120 colleges and universities, including Columbia University, New York University, and the City University of New York system, which is the largest urban public university system in the United States. Anchored by Wall Street in the Financial District of Lower Manhattan, New York City has been called both the world's leading financial center and the most powerful city in the world,^[35] and is home to the world's two largest stock exchanges by total market capitalization, the New York Stock Exchange and Nasdaq.^[36][37]

San Francisco (/ˌsæn frənˈsɪskoʊ/; Spanish for "Saint Francis"), officially the City and County of San Francisco, is a cultural, commercial, and financial center in the U.S. state of California. Located in Northern California, San Francisco is the 17th most populous city proper in the United States, and the fourth most populous in California, with 873,965 residents as of 2020.[15] It covers an area of about 46.9 square miles (121 square kilometers),[20] mostly at the north end of the San Francisco Peninsula in the San Francisco Bay Area, making it the second most densely populated large U.S. city, and the fifth most densely populated U.S. county, behind only four of the five New York City boroughs. San Francisco is the 12th-largest metropolitan statistical area in the United States with 4.7 million residents, and the fourth-largest by economic output, with a GDP of $592 billion in 2019.[21] With San Jose, California, it forms the San Jose–San Francisco–Oakland, CA Combined Statistical Area, the fifth most populous combined statistical area in the United States, with 9.6 million residents as of 2019. Colloquial nicknames for San Francisco include SF, San Fran, The City, and Frisco.[22][23]

In 2019, San Francisco was the county with the seventh-highest income in the United States, with a per capita income of $139,405.[24] In the same year, San Francisco proper had a GDP of $203.5 billion, and a GDP per capita of $230,829.[21][25] The San Jose–San Francisco–Oakland, CA Combined Statistical Area, with a GDP of $1.09 trillion as of 2019, is the country's third-largest economy.[26] Of the 105 primary statistical areas in the U.S. with over 500,000 residents, this CSA had the highest GDP per capita in 2019, at $112,348.[26] San Francisco was ranked 5th in the world and second in the United States on the Global Financial Centres Index as of September 2021.[27]

San Francisco was founded on June 29, 1776, when colonists from Spain established the Presidio of San Francisco at the Golden Gate and Mission San Francisco de Asís a few miles away, both named for Francis of Assisi.[3] The California Gold Rush of 1849 brought rapid growth, making it the largest city on the West Coast at the time; between 1870 and 1900, approximately one quarter of California's population resided in the city proper.[28] In 1856, San Francisco became a consolidated city-county.[29] After three-quarters of the city was destroyed by the 1906 earthquake and fire,[30] it was quickly rebuilt, hosting the Panama-Pacific International Exposition nine years later. In World War II, it was a major port of embarkation for service members shipping out to the Pacific Theater.[31] It then became the birthplace of the United Nations in 1945.[32][33][34] After the war, the confluence of returning servicemen, significant immigration, liberalizing attitudes, the rise of the "beatnik" and "hippie" countercultures, the Sexual Revolution, the Peace Movement growing from opposition to United States involvement in the Vietnam War, and other factors led to the Summer of Love and the gay rights movement, cementing San Francisco as a center of liberal activism in the United States. Politically, the city votes strongly along liberal Democratic Party lines.

A popular tourist destination,[35] San Francisco is known for its cool summers, fog, steep rolling hills, eclectic mix of architecture, and landmarks, including the Golden Gate Bridge, cable cars, the former Alcatraz Federal Penitentiary, Fisherman's Wharf, and its Chinatown district. San Francisco is also the headquarters of companies such as Wells Fargo, Twitter, Block, Airbnb, Levi Strauss & Co., Gap Inc., Salesforce, Dropbox, Pacific Gas and Electric Company, Uber, and Lyft. The city, and the surrounding Bay Area, is a global center of the sciences and arts[36][37] and is home to a number of educational and cultural institutions, such as the University of California, San Francisco (UCSF), the University of San Francisco (USF), San Francisco State University (SFSU), the de Young Museum, the San Francisco Museum of Modern Art, the SFJAZZ Center, the San Francisco Symphony and the California Academy of Sciences. More recently, statewide droughts in California have strained the city's water security.