Metropolitan Statistical Area (MSA) is a designation the U.S. government uses to refer to a region that, broadly speaking, consists of a city and its suburbs, plus any surrounding communities that are closely linked to the city economically and socially. MSAs were known as Standard Metropolitan Statistical Areas (SMSAs) from 1959 to 1983 and, before that, as Standard Metropolitan Areas (SMAs). Having some familiarity with MSAs is useful to businesspeople, since data about these regions can be helpful in devising marketing strategies, delineating sales territories, and determining the locations of plant and operating facilities.


The government uses the designation "MSA" for the purpose of applying uniform and consistent standards to the wealth of data collected, analyzed, and published by its myriad departments and agencies. Official definitions for what constitutes an MSA are developed, issued, and periodically revised by the federal Office of Management and Budget (OMB), following public commentary and hearings and in conjunction with the Federal Executive Committee on Metropolitan Areas. And because MSA and similar designations figure prominently in the compilation of statistics for the national census, the U.S. Department of Commerce's Bureau of the Census also plays a part in refining the definitions. Census data, both from the major decennial censuses and smaller interim ones, are used to revise MSA definitions.

Although the OMB's official standards for defining these regions are highly complex, detailed, and marked by qualifications, in general MSAs can be viewed as part of larger entities known as Metropolitan Areas (MAs). MAs are regions composed of one or more counties and containing either (a) a city whose population is at least 50,000 or (b) a Census Bureau-defined "urbanized area" whose population, together with that of its component county or counties, totals at least 100,000. An important exception to how MAs are defined concerns the New England states, where towns and cities rather than counties are used to designate regions as MAs.

Within the broad category of MAs are three elements, or subcategories: (a) MSAs, generally constituting free-standing MAs whose surrounding counties are nonmetropolitan; (b) Consolidated Metropolitan Statistical Areas (CMSAs), representing the largest metropolitan regions, those with populations of more than one million; and (c) Primary Metropolitan Statistical Areas (PMSAs), consisting of the individual urbanized counties or county clusters within CMSAs. It is, however, possible for an MSA to be larger than a CMS A, depending on the geographic dispersion of the population in a particular metropolitan area.


Population figures reflect the importance of these categories for statistical and demographic purposes. Based on 1996 Census Bureau estimates, 212 million of the United States' 265 million residents—just under 80 percent—lived in 273 metropolitan areas, as defined by MSAs and CMSAs. The top 20 areas alone reported 112 million people, or 42 percent of the U.S. population. The New York City CMSA, which includes portions of northern New Jersey and Connecticut, is the largest, with approximately 20 million inhabitants. The other top five consolidated areas include Los Angeles-Long Beach, with 15.5 million; Chicago-Gary-Kenosha, with 8.6 million; Washington, D.C.-Baltimore, with 7.2 million; and San Francisco-Oakland-San Jose, with 6.6 million.

There are 18 such CMSAs in total, and they support some 103 million residents. Between 1990 and 1996, these areas combined added more than 5.4 million residents to their populations. According to tabulations published in 1998 by the magazine Industry Week, the CMSAs accounted for around 43 percent of all U.S. manufacturing activity in value.


Information on the OMB's standards for defining MSAs and other such designations can be obtained from the Statistical Policy Office of the Office of Information and Regulatory Affairs, Office of Management and Budget in Washington, D.C. Information on the Census Bureau's application of these standards is available from the Secretary of the Federal Executive Committee on Metropolitan Areas, Population Division, U.S. Bureau of the Census, also in Washington, D.C.

[ Roberta H. Winston ]


Office of Management and Budget. "Revised Standards for Defining Metropolitan Areas in the 1990s; Notice." Federal Register. April 10, April 30, and 10 May 1990.

Purdi, Traci, and Edward W. Hill. "Generating Wealth: Eighteen CMSAs Contribute a Huge Chunk of Manufacturing Value in the U.S." Industry Week, 6 April 1998. Available from .

U.S. Bureau of the Census. Estimates of the Population of Metropolitan Areas. Washington, annual. Available from .

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