United States metropolitan area
Metropolitan Statistical Areas (MSA) are large metropolitan areas of the United States as defined by the Office of Management and Budget. These areas are urban areas with a lot of people. An earlier version of the MSA was the "Standard Metropolitan Statistical Area" (SMSA). MSAs are used for official purposes.
MSAs are made up of counties and for some county equivalents. In New England, because of the greater importance of towns over counties, similar areas are based on town units. These are called New England City and Town Areas (NECTAs).
MSAs are created around a central urban area —an areawhere there are a lot of people. The counties with the urbanized area are known as the central counties of the MSA. Other nearby counties (known as outlying counties) can be a part of the MSA if these counties have strong social and economic connections to the central counties. Some areas within these outlying counties may actually be rural areas.
The population estimates for some metro areas are not always agreed upon. In some cases, different sources give numbers of people which differ by millions. The definitions used for the last U.S. Census differed from those for previous censuses. This makes it hard to compare official information from different dates. MSA boundaries do not stretch into Canada or Mexico. This can affect the number of people in several cities. For example, Detroit, Buffalo, El Paso and San Diego are often much larger than their MSA figures.
As of June 2003, there is now an additional classification, “Metropolitan Division.” The term metropolitan division is used for a county or group of counties that are a distinct employment area within a metropolitan statistical area that has at least 2.5 million people. A metropolitan division is a part of a larger metropolitan statistical area but it is often a distinct social, economic, and cultural area within the larger region.
- For all U.S. Metropolitan Statistical Areas, see the Table of United States Metropolitan Statistical Areas.
- For a list including combined metropolitan areas, see the Table of United States primary census statistical areas.
- Census Geographic Glossary, U.S. Census Bureau
- This population is only for the United States side. The area is also included together with the city of Tijuana in Mexico in the bi-national conurbation known as the San Diego-Tijuana Metropolitan Area which together have 4,945,410 people.