2003 Metropolitan and Micropolitan Statistical Areas
Source: The Census Bureau

The United States Office of Management and Budget (OMB) defines metropolitan 
and micropolitan statistical areas according to published standards that are 
applied to Census Bureau data. The general concept of a metropolitan or 
micropolitan statistical area is that of a core area containing a substantial 
population nucleus, together with adjacent communities having a high degree of 
economic and social integration with that core. Currently defined metropolitan 
and micropolitan statistical areas are based on application of 2000 standards 
(which appeared in the Federal Register on December 27, 2000) to 2000 decennial 
census data. Current metropolitan and micropolitan statistical area definitions 
were announced by OMB effective June 6, 2003.

Standard definitions of metropolitan areas were first issued in 1949 by the 
then Bureau of the Budget (predecessor of OMB), under the designation "standard 
metropolitan area" (SMA). The term was changed to "standard metropolitan 
statistical area" in 1959, and to "metropolitan statistical area" (MSA) in 1983. 
The term "metropolitan area" (MA) was adopted in 1990 and referred collectively 
to metropolitan statistical areas (MSAs), consolidated metropolitan statistical 
areas (CMSAs), and primary metropolitan statistical areas (PMSAs). The term 
"core based statistical area" (CBSA) became effective in 2000 and refers 
collectively to metropolitan and micropolitan statistical areas.

OMB has been responsible for the official metropolitan areas since they were 
first defined, except for the period 1977 to 1981, when they were the 
responsibility of the Office of Federal Statistical Policy and Standards, 
Department of Commerce. The standards for defining metropolitan areas were 
modified in 1958, 1971, 1975, 1980, 1990, and 2000.

Defining Metropolitan and Micropolitan Statistical Areas

The 2000 standards provide that each CBSA must contain at least one urban area 
of 10,000 or more population. Each metropolitan statistical area must have at 
least one urbanized area of 50,000 or more inhabitants. Each micropolitan 
statistical area must have at least one urban cluster of at least 10,000 but 
less than 50,000 population.

Under the standards, the county (or counties) in which at least 50 percent of 
the population resides within urban areas of 10,000 or more population, or that 
contain at least 5,000 people residing within a single urban area of 10,000 or 
more population, is identified as a "central county" (counties). Additional 
"outlying counties" are included in the CBSA if they meet specified requirements 
of commuting to or from the central counties. Counties or equivalent entities 
form the geographic "building blocks" for metropolitan and micropolitan 
statistical areas throughout the United States and Puerto Rico.

If specified criteria are met, a metropolitan statistical area containing a 
single core with a population of 2.5 million or more may be subdivided to form 
smaller groupings of counties referred to as "metropolitan divisions."

As of June 6, 2003, there are 362 metropolitan statistical areas and 560 
micropolitan statistical areas in the United States. In addition, there are 8 
metropolitan statistical areas and 5 micropolitan statistical areas in Puerto 
Rico.

Principal Cities and Metropolitan and Micropolitan Statistical Area Titles

The largest city in each metropolitan or micropolitan statistical area is 
designated a "principal city." Additional cities qualify if specified 
requirements are met concerning population size and employment. The title of 
each metropolitan or micropolitan statistical area consists of the names of up 
to three of its principal cities and the name of each state into which the 
metropolitan or micropolitan statistical area extends. Titles of metropolitan 
divisions also typically are based on principal city names but in certain cases 
consist of county names.

Defining New England City and Town Areas

In view of the importance of cities and town in New England, the 2000 standards 
also provide for a set of geographic areas that are defined using cities and 
towns in the six New England states. The New England city and town areas 
(NECTAs) are defined using the same criteria as metropolitan and micropolitan 
statistical areas and are identified as either metropolitan or micropolitan, 
based, respectively, on the presence of either an urbanized area of 50,000 or 
more population or an urban cluster of at least 10,000 but less than 50,000 
population. If the specified criteria are met, a NECTA containing a single core 
with a population of at least 2.5 million may be subdivided to form smaller 
groupings of cities and towns referred to as New England city and
town area divisions.

Changes in Definitions over Time

Changes in the definitions of these statistical areas since the 1950 census 
have consisted chiefly of:

*the recognition of new areas as they reached the minimum required city or 
 urbanized area population, and

*the addition of counties (or cities and towns in New England) to existing 
 areas as new decennial census data showed them to qualify.

In some instances, formerly separate areas have been merged, components of an 
area have been transferred from one area to another, or components have been 
dropped from an area. The large majority of changes have taken place on the 
basis of decennial census data. However, Census Bureau data serve as the basis 
for intercensal updates in specified circumstances.

Because of these historical changes in geographic definitions, users must be 
cautious in comparing data for these statistical areas from different dates. 
For some purposes, comparisons of data for areas as defined at given dates may 
be appropriate; for other purposes, it may be preferable to maintain consistent 
area definitions. Historical metropolitan area definitions are available for 
1999, 1993, 1990, 1983, 1981, 1973, 1970, 1963, 1960, and 1950.

For more information, contact the Population Distribution Branch at 
(301) 763-2419.

Source: U.S. Census Bureau, 
Population Division,
Population Distribution Branch
Maintained By: Laura K. Yax (Population Division)
Last Revised: June 12, 2003 at 09:09:18 AM 

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2003 Metropolitan and Micropolitan Statistical Areas
Source: Office of Management and Budget

Metropolitan Statistical Areas have at least one urbanized area of 50,000 or 
more population, plus adjacent territory that has a high degree of social and 
economic integration with the core as measured by commuting ties. Micropolitan 
Statistical Areas  a new set of statistical areas  have at least one urban
cluster of at least 10,000 but less than 50,000 population, plus adjacent 
territory that has a high degree of social and economic integration with the 
core as measured by commuting ties. Metropolitan and Micropolitan Statistical 
Areas are defined in terms of whole counties (or equivalent entities), including 
in the six New England States. If the specified criteria are met, a Metropolitan 
Statistical Area containing a single core with a population of 2.5 million or 
more may be subdivided to form smaller groupings of counties referred to as 
Metropolitan Divisions.

The classification includes about 93 percent of the U.S. population  about 83 
percent in metropolitan statistical areas and about 10 percent in micropolitan 
statistical areas. (Previously, the classification included about 80 percent of 
the U.S. population.) Of 3,142 counties in the United States (the 3,141 counties 
at the time of the 2000 decennial census plus Broomfield, Colorado, which became 
a county in November 2001), 1,090 will be in the 362 metropolitan statistical 
areas in the United States and 674 counties will be in micropolitan statistical 
areas (1,378 counties will remain outside the classification). (Previously, the 
classification included 847 metropolitan counties.)

In view of the importance of cities and town in New England, the 2000 standards 
also provide for a set of geographic areas that are defined using cities and 
towns in the six New England states. The New England City and Town Areas 
(NECTAs)are defined using the same criteria as Metropolitan and Micropolitan 
Statistical Areas and are identified as either metropolitan or micropolitan, 
based, respectively, on the presence of either an urbanized area of 50,000 or 
more population or an urban cluster of at least 10,000 but less than 50,000 
population. If the specified criteria are met, a New England City and Town Area 
containing a single core with a population of at least 2.5 million may be 
subdivided to form smaller groupings of cities and towns referred to as New 
England City and Town Area Divisions.

If specified criteria are met, adjacent Metropolitan and Micropolitan 
Statistical Areas, in various combinations, may become the components of a new 
set of areas called Combined Statistical Areas. For instance, a Combined 
Statistical Area may comprise two or more Metropolitan Statistical Areas, a
Metropolitan Statistical Area and a Micropolitan Statistical Area, two or more 
Micropolitan Statistical Areas, or multiple Metropolitan and Micropolitan 
Statistical Areas. The geographic components of Combined New England City 
and Town Areas are individual metropolitan and micropolitan NECTAs, in various 
combinations. The areas that combine retain their own designations as 
Metropolitan or Micropolitan Statistical Areas (or NECTAs) within the larger C
ombined Statistical Area (or Combined NECTAs). Combinations for adjacent areas 
with an employment interchange of 25 or more are automatic. Combinations for 
adjacent areas with an employment interchange of at least 15 but less than
25 are based on local opinion as expressed through the Congressional 
delegations.

OMBs standards provide for the identification of one or more principal cities 
within each Metropolitan Statistical Area, Micropolitan Statistical Area, and 
NECTA. (The term principal city  replaces central city, the term used in 
previous standards.) Principal cities encompass both incorporated places and
census designated places (CDPs). The decision to identify CDPs as principal 
cities represents a break with practice in previous standards that (with some 
exceptions)limited potential central city identification to incorporated places. 
In addition to identifying the more significant places in each Metropolitan and
Micropolitan Statistical Area or NECTA in terms of population and employment, 
principal cities also are used in titling Metropolitan and Micropolitan 
Statistical Areas, Metropolitan Divisions, Combined Statistical Areas, NECTAs,
NECTA Divisions, and Combined NECTAs.

The geographic components of Metropolitan and Micropolitan Statistical Areas and 
Metropolitan Divisions are counties and equivalent entities (boroughs and census 
areas in Alaska, parishes in Louisiana, municipios in Puerto Rico, and 
independent cities in Maryland, Missouri, Nevada, and Virginia). The counties 
and equivalent entities used in the definitions of the Metropolitan and 
Micropolitan Statistical Areas are those that were in existence as of 
January 1, 2000, with the exception of Broomfield County, Colorado.

The 2000 standards do not provide for the categorization of the areas based on 
total population comparable to Levels A  D under the 1990 standards.

MSA 2003 Summary

    Metropolitan Statistical Areas             370
    Micropolitan Statistical Areas             565
                                             -----
    Core Based Statistical Areas (CBSAs)       935

    Combined Statistical Areas                 116
    Metropolitan Divisions                      29

Source: Office of Management and Budget
OMB Bulletin No.03-04
Attachment

