Agglomerations

Leading population centers (see complete list)
Rank	Core city (cities)	Metro area population	Metropolitan Statistical Area	Region	New York City Los Angeles Chicago Dallas
1	New York City	20,320,876	New York–Newark–Jersey City, NY–NJ–PA MSA	Northeast
2	Los Angeles	13,353,907	Los Angeles–Long Beach–Anaheim, CA MSA	West
3	Chicago	9,533,040	Chicago–Joliet–Naperville, IL–IN–WI MSA	Midwest
4	Dallas–Fort Worth	7,399,662	Dallas–Fort Worth–Arlington, TX MSA	South
5	Houston	6,892,427	Houston–The Woodlands-Sugar Land MSA	South
6	Washington, D.C.	6,216,589	Washington, DC–VA–MD–WV MSA	South
7	Miami	6,158,824	Miami–Fort Lauderdale–West Palm Beach, FL MSA	South
8	Philadelphia	6,096,120	Philadelphia–Camden–Wilmington, PA–NJ–DE–MD MSA	Northeast
9	Atlanta	5,884,736	Atlanta–Sandy Springs–Roswell, GA MSA	South
10	Boston	4,836,531	Boston–Cambridge–Quincy, MA–NH MSA	Northeast
11	Phoenix	4,737,270	Phoenix–Mesa–Chandler, AZ MSA	West
12	San Francisco	4,727,357	San Francisco–Oakland–Fremont, CA MSA	West
13	Riverside–San Bernardino	4,580,670	Riverside–San Bernardino–Ontario, CA MSA	West
14	Detroit	4,313,002	Detroit-Warren-Dearborn, MI MSA	Midwest
15	Seattle	3,867,046	Seattle–Tacoma–Bellevue, WA MSA	West
16	Minneapolis–St. Paul	3,600,618	Minneapolis–St. Paul–Bloomington, MN–WI MSA	Midwest
17	San Diego	3,337,685	San Diego–Carlsbad–San Marcos, CA MSA	West
18	Tampa–St. Petersburg	3,091,399	Tampa–St. Petersburg–Clearwater, FL MSA	South
19	Denver	2,888,227	Denver–Aurora–Lakewood, CO MSA	West
20	Baltimore	2,808,175	Baltimore-Columbia-Towson, MD MSA	South
Based on 2017 MSA population estimates from the U.S. Census Bureau

An urban area is a human settlement with high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, towns, conurbations or suburbs. In urbanism, the term contrasts to rural areas such as villages and hamlets and in urban sociology or urban anthropology it contrasts with natural environment. The creation of early predecessors of urban areas during the urban revolution led to the creation of human civilization with modern urban planning, which along with other human activities such as exploitation of natural resources leads to human impact on the environment.

The world's urban population in 1950 of just 746 million has increased to 3.9 billion in the decades since. In 2009, the number of people living in urban areas (3.42 billion) surpassed the number living in rural areas (3.41 billion) and since then the world has become more urban than rural. This was the first time that the majority of the world's population lived in a city. In 2014 there were 7.2 billion people living on the planet, of which the global urban population comprised 3.9 billion. The Population Division of the United Nations Department of Economic and Social Affairs at that time predicted the urban population would grow to 6.4 billion by 2050, with 37% of that growth to come from three countries: China, India and Nigeria.

...
Wikipedia