Columbus is the state capital and the most populous city in the U.S. state of Ohio. With a population of 905,748 for the 2020 census,[4] it is the 14th-most populous city in the U.S., the second-most populous city in the Midwest after Chicago, and the third-most populous state capital. Columbus is the county seat of Franklin County; it also extends into Delaware and Fairfield counties.[9] It is the core city of the Columbus, OH Metropolitan Statistical Area, which encompasses ten counties.[10] The metropolitan area has a 2020 population of 2,138,926, making it the largest entirely in Ohio.[a]

Columbus originated as numerous Native American settlements on the banks of the Scioto River. Franklinton, now a city neighborhood, was the first European settlement, laid out in 1797. The city was founded in 1812, at the confluence of the Scioto and Olentangy rivers, and laid out to become the state capital. The city was named for Italian explorer Christopher Columbus.[12] The city assumed the function of state capital in 1816 and county seat in 1824. Amid steady years of growth and industrialization, the city has experienced numerous floods and recessions. Beginning in the 1950s, Columbus began to experience significant growth; it became the largest city in Ohio in land and population by the early 1990s. The 1990s and 2000s saw redevelopment in numerous city neighborhoods, including downtown.

The city has a diverse economy based on education, government, insurance, banking, defense, aviation, food, clothes, logistics, steel, energy, medical research, health care, hospitality, retail, and technology. The metropolitan area is home to the Battelle Memorial Institute, the world's largest private research and development foundation; Chemical Abstracts Service, the world's largest clearinghouse of chemical information; and Ohio State University, one of the largest universities in the United States. As of 2021, the Greater Columbus area is home to the headquarters of six corporations in the U.S. Fortune 500: Cardinal Health, American Electric Power, L Brands, Nationwide, Alliance Data, and Huntington Bancshares.

Philadelphia (colloquially known simply as Philly) is the largest city in the Commonwealth of Pennsylvania in the United States. It is the sixth-most-populous city in the United States and the most populous city in the state of Pennsylvania, with a 2020 population of 1,603,797.[6] It is also the second-most populous city in the Northeastern United States, behind New York City. Since 1854, the city has had the same geographic boundaries as Philadelphia County, the most-populous county in Pennsylvania and the urban core of the eighth-largest U.S. metropolitan statistical area, with over 6 million residents as of 2017.[9] Philadelphia is also the economic and cultural center of the greater Delaware Valley along the lower Delaware and Schuylkill rivers within the Northeast megalopolis. The Delaware Valley's 2019 estimated population of 7.21 million makes it the ninth-largest combined statistical area in the United States.[10]

Philadelphia is one of the oldest municipalities in the United States. William Penn, an English Quaker, founded the city in 1682 to serve as capital of the Pennsylvania Colony.[4][11] Philadelphia played an instrumental role in the American Revolution as a meeting place for the Founding Fathers of the United States, who signed the Declaration of Independence in 1776 at the Second Continental Congress, and the Constitution at the Philadelphia Convention of 1787. Several other key events occurred in Philadelphia during the Revolutionary War including the First Continental Congress, the preservation of the Liberty Bell, the Battle of Germantown, and the Siege of Fort Mifflin. Philadelphia remained the nation's largest city until being overtaken by New York City in 1790; the city was also one of the nation's capitals during the revolution, serving as temporary U.S. capital while Washington, D.C. was under construction.

In the 19th and 20th centuries, Philadelphia became a major industrial center and a railroad hub. The city grew due to an influx of European immigrants, most of whom initially came from Ireland and Germany—the two largest reported ancestry groups in the city as of 2015. Later immigrant groups in the 20th century came from Italy (Italian being the third largest European ethnic ancestry currently reported in Philadelphia) and other Southern European and Eastern European countries.[12] In the early 20th century, Philadelphia became a prime destination for African Americans during the Great Migration after the Civil War.[13] Puerto Ricans began moving to the city in large numbers in the period between World War I and II, and in even greater numbers in the post-war period.[14] The city's population doubled from one million to two million people between 1890 and 1950.

The Philadelphia area's many universities and colleges make it a top study destination, as the city has evolved into an educational and economic hub.[15][16] As of 2019, the Philadelphia metropolitan area is estimated to produce a gross metropolitan product (GMP) of $490 billion.[17] Philadelphia is the center of economic activity in Pennsylvania and is home to five Fortune 1000 companies. The Philadelphia skyline is expanding, with a market of almost 81,900 commercial properties in 2016,[18] including several nationally prominent skyscrapers.[19] Philadelphia has more outdoor sculptures and murals than any other American city.[20][21] Fairmount Park, when combined with the adjacent Wissahickon Valley Park in the same watershed, is one of the largest contiguous urban park areas in the United States.[22] The city is known for its arts, culture, cuisine, and colonial history, attracting 42 million domestic tourists in 2016 who spent $6.8 billion, generating an estimated $11 billion in total economic impact in the city and surrounding four counties of Pennsylvania.[23] Philadelphia is also a biotechnology hub.[24]

Philadelphia is the home of many U.S. firsts, including the nation's first library (1731),[25] hospital (1751),[25] medical school (1765),[26] national capital (1774),[27] university (by some accounts) (1779),[28] stock exchange (1790),[25] zoo (1874),[29] and business school (1881).[30] Philadelphia contains 67 National Historic Landmarks and the World Heritage Site of Independence Hall.[31] The city became a member of the Organization of World Heritage Cities in 2015,[32] as the first World Heritage City in the United States.

Portland (/ˈpɔːrtlənd/, PORT-lənd) is a city of regional importance to the Pacific Northwest and the largest and most populous city in the U.S. state of Oregon. Within Oregon it is the sub-regional seat of power for Multnomah County, the largest county in Oregon by population. It is also an inland port city in the Willamette Valley region of the Pacific Northwest, at the confluence of the Willamette and Columbia rivers in Northwestern Oregon. As of 2020, Portland had a population of 652,503,[8] making it the 25th-most populated city in the United States, the sixth-most populous on the West Coast, and the second-most populous in the Pacific Northwest, after Seattle.[9] Approximately 2.5 million people live in the Portland metropolitan statistical area (MSA), making it the 25th most populous in the United States. Its combined statistical area (CSA) ranks 19th-largest with a population of around 3.2 million. Approximately 47% of Oregon's population resides within the Portland metropolitan area.[a]

Named after Portland, Maine,[10] the Oregon settlement began to be populated in the 1830s, near the end of the Oregon Trail. Its water access provided convenient transportation of goods, and the timber industry was a major force in the city's early economy. At the turn of the 20th century, the city had a reputation as one of the most dangerous port cities in the world, a hub for organized crime and racketeering. After the city's economy experienced an industrial boom during World War II, its hard-edged reputation began to dissipate. Beginning in the 1960s,[11] Portland became noted for its growing progressive political values, earning it a reputation as a bastion of counter-culture.[12]

The city operates with a commission-based government, guided by a mayor and four commissioners, as well as Metro, the only directly elected metropolitan planning organization in the United States.[13] Its climate is marked by warm, dry summers and cool, rainy winters. This climate is ideal for growing roses, and Portland has been called the "City of Roses" for over a century.

Washington, D.C., formally the District of Columbia and commonly referred to as Washington or D.C., is the capital of the United States of America.[4] Founded after the American Revolution as the seat of government of the newly independent country, Washington was named after George Washington, first President of the United States and Founding Father.[5] Washington is the principal city of the Washington metropolitan area, which has a population of 6,131,977.[6] As the seat of the United States federal government and several international organizations, the city is an important world political capital.[7] Washington is one of the most visited cities in the world, with more than 20 million annual tourists.[8][9]

The signing of the Residence Act on July 16, 1790, approved the creation of a capital district located along the Potomac River on the country's East Coast. The U.S. Constitution provided for a federal district under the exclusive jurisdiction of the Congress and the District is therefore not a part of any state. The states of Maryland and Virginia each donated land to form the federal district, which included the pre-existing settlements of Georgetown and Alexandria. Named in honor of President George Washington, the City of Washington was founded in 1791 to serve as the new national capital. In 1846, Congress returned the land originally ceded by Virginia; in 1871, it created a single municipal government for the remaining portion of the District.

Washington had an estimated population of 693,972 as of July 2017, making it the 20th largest American city by population. Commuters from the surrounding Maryland and Virginia suburbs raise the city's daytime population to more than one million during the workweek. The Washington metropolitan area, of which the District is the principal city, has a population of over 6 million, the sixth-largest metropolitan statistical area in the country.

All three branches of the U.S. federal government are centered in the District: U.S. Congress (legislative), President (executive), and the U.S. Supreme Court (judicial). Washington is home to many national monuments and museums, which are primarily situated on or around the National Mall. The city hosts 177 foreign embassies as well as the headquarters of many international organizations, trade unions, non-profit, lobbying groups, and professional associations, including the Organization of American States, AARP, the National Geographic Society, the Human Rights Campaign, the International Finance Corporation, and the American Red Cross.

A locally elected mayor and a 13‑member council have governed the District since 1973. However, Congress maintains supreme authority over the city and may overturn local laws. D.C. residents elect a non-voting, at-large congressional delegate to the House of Representatives, but the District has no representation in the Senate. The District receives three electoral votes in presidential elections as permitted by the Twenty-third Amendment to the United States Constitution, ratified in 1961.