kids encyclopedia robot

Metropolitan statistical area facts for kids

Kids Encyclopedia Facts


In the United States, a metropolitan statistical area (MSA) is a large geographic area where many people live close together in a main city and its surrounding towns. These areas are also connected by strong economic ties, meaning people often travel between them for work or business. MSAs are not official cities or towns, and they are not legal administrative divisions like counties. Because of this, the exact boundaries of an MSA can sometimes be a bit different depending on who is defining them. The idea of these areas was first set up in 1949 and then updated in 1983.

A typical metropolitan area often has more than one big city at its heart, not just one. This is because many jobs and people have moved to the suburbs over time. Famous examples include New York City and Chicago. Some MSAs even have several large main cities, like the Dallas–Fort Worth metroplex, Virginia Beach–Norfolk–Newport News, and Minneapolis–Saint Paul.

The Office of Management and Budget (OMB), which is part of the U.S. President's office, defines these MSAs. The U.S. Census Bureau and other government groups then use these definitions to collect and study information about populations.

Understanding Metropolitan Areas

Metropolitan and Micropolitan Statistical Areas (CBSAs) of the United States and Puerto Rico, Mar 2020
An enlargeable map of the 939 core-based statistical areas (CBSAs) of the United States and Puerto Rico as of 2020; the 384 MSAs are shown in medium green     . In 2023, OMB revised the delineations of these CBSAs.

The U.S. Office of Management and Budget (OMB) creates a set of areas called core based statistical areas (CBSAs). These CBSAs are made up of counties or similar areas.

CBSAs are built around a main area where many people live, known as an urban area. The counties that contain this main urban area are called "central counties." At least half of the people in these central counties must live in urban areas with 10,000 or more residents. Other counties nearby, called "outlying counties," can be added to a CBSA if they have strong connections to the central county. These connections are measured by how many people travel for work between the counties. For example, if 25% of workers in an outlying county work in the central county, it can be included.

Sometimes, nearby CBSAs are combined into a larger area called a combined statistical area (CSA). This happens when there's a lot of job exchange between them, meaning many people commute between these areas for work.

CBSAs are divided into two main types:

  • Metropolitan Statistical Areas (MSAs): These are formed around urban areas with at least 50,000 people.
  • Micropolitan Statistical Areas (μSAs): These are built around urban areas with at least 10,000 people, but less than 50,000.

Even if a metropolitan area has several smaller cities, if their combined population is over 50,000, it can still be an MSA.

In 2021, the OMB thought about raising the minimum population for an MSA to 100,000, but they decided to keep it at 50,000 for the 2020 count. The OMB updated the definitions for these areas again on July 21, 2023.

How Metropolitan Areas Began

The Census Bureau first created "metropolitan districts" for the 1910 census. This was a way to group large cities and their surrounding areas. At first, a district needed 200,000 people. This number was later lowered to 100,000 in 1930 and then to 50,000 in 1940.

These districts were replaced by "standard metropolitan areas" (SMAs) for the 1950 census. The Bureau of the Budget (now the OMB) defined these. They were later renamed "standard metropolitan statistical areas" (SMSAs) in 1959. The modern "metropolitan statistical area" (MSA) was created in 1983. This happened as more and more areas met the requirements, growing from 172 in 1950 to 288 in 1980. The idea of a "core based statistical area" (CBSA) was introduced in 2000 and defined in 2003. This new definition set the minimum population at 10,000 for micropolitan areas and 50,000 for urban areas.

Top Metropolitan Areas in the U.S.

Here's a list of the largest metropolitan statistical areas in the United States. This includes areas in all 50 states and Washington, D.C.. The list shows:

  • The MSA's rank by population as of July 1, 2023. This is an estimate from the United States Census Bureau.
  • The MSA's name, as decided by the U.S. Office of Management and Budget.
  • The MSA's population on July 1, 2023 (estimated).
  • The MSA's population on April 1, 2020 (counted in the 2020 United States census).
  • How much the MSA's population changed from April 1, 2020, to July 1, 2023.
  • The combined statistical area (CSA) it belongs to, if it's part of a larger group.


Metropolitan Areas in Puerto Rico

This table lists the six metropolitan statistical areas (MSAs) in Puerto Rico. It shows:

  • The MSA's rank by population as of July 1, 2023. This is an estimate from the United States Census Bureau.
  • The MSA's name, as decided by the U.S. Office of Management and Budget.
  • The MSA's population on July 1, 2023 (estimated).
  • The MSA's population on April 1, 2020 (counted in the 2020 United States census).
  • How much the MSA's population changed from April 1, 2020, to July 1, 2023.
  • The combined statistical area (CSA) it belongs to, if it's part of a larger group.
The six metropolitan statistical areas of the Commonwealth of Puerto Rico
Rank Metropolitan statistical area 2023 estimate 2020 census Change Encompassing combined statistical area
&&&&&&&&&&&&&&01.&&&&&01 San Juan–Bayamón–Caguas, PR MSA 2,035,733 2,081,265 Template:Number table sorting/negative−2.19% San Juan–Bayamón, PR Combined Statistical Area
&&&&&&&&&&&&&&02.&&&&&02 Ponce, PR MSA 266,237 278,477 Template:Number table sorting/negative−4.40% Ponce–Coamo, PR Combined Statistical Area
&&&&&&&&&&&&&&03.&&&&&03 Aguadilla, PR MSA 250,435 253,768 Template:Number table sorting/negative−1.31% Mayagüez–Aguadilla, PR Combined Statistical Area
&&&&&&&&&&&&&&04.&&&&&04 Mayagüez, PR MSA 207,877 213,831 Template:Number table sorting/negative−2.78% Mayagüez–Aguadilla, PR Combined Statistical Area
&&&&&&&&&&&&&&05.&&&&&05 Arecibo, PR MSA 179,470 182,705 Template:Number table sorting/negative−1.77% San Juan–Bayamón, PR Combined Statistical Area
&&&&&&&&&&&&&&06.&&&&&06 Guayama, PR MSA 65,190 68,442 Template:Number table sorting/negative−4.75% San Juan–Bayamón, PR Combined Statistical Area

See also

Kids robot.svg In Spanish: Área estadística metropolitana para niños

*Metropolitan statistical area (list) *Micropolitan statistical area (list)

kids search engine
Metropolitan statistical area Facts for Kids. Kiddle Encyclopedia.