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Core Based Statistical Area (CBSA) Definitions
April 5, 2025
Metropolitan Statistical Areas (MSAs), Combined Statistical Areas (CSAs), Micropolitan Statistical Areas (MICROs), and Metropolitan Divisions (MDIVs) in the Woods & Poole database are as defined in the July 2023, Office of Management and Budget (OMB BULLETIN NO. 23-01), “Revised Delineations of Metropolitan Statistical Areas, Micropolitan Statistical Areas, and Combined Statistical Areas, and Guidance on Uses of the Delineations of These Areas”, except for metros containing Connecticut planning regions.
All Woods & Poole historical data back to 1969 are revised to reflect the new 2023 OMB. Metropolitan Area (MSA, CSA, MICRO, and MDIV) definitions, except for metros containing Connecticut planning regions which are based on 2020 OMB definitions based on Connecticut legacy counties. There are 385 MSAs, 181 CSAs, 536 MICROs, and 37 MDIVs in the 2024 Woods & Poole database.
OMB 2023 metro areas that include one or more Connecticut planning region are not included in the 2024 Woods & Poole database. The following OMB July 2023 metro areas are not included (FIPS codes in parentheses): Boston-Worcester-Providence, MA-RI-NH CSA (148), New Haven-Hartford-Waterbury, CT CSA (405), New York-Newark, NY-NJ-CT-PA CSA (408), Bridgeport-Stamford, Danbury, CT MSA (14860), Hartford-West Hartford-East Hartford, CT MSA (25540), New Haven, CT MSA (35300), Norwich-New London-Willimantic, CT MSA (35980),Waterbury-Shelton, CT MSA (47930),Worcester, MA MSA (49340), Putnam, CT MICRO (39480), and Torrington, CT MICRO (45860). OMB 2020 (OMB BULLETIN NO. 20-01) metro areas that include one or more Connecticut legacy county are included in the 2024 Woods & Poole database. The following OMB March 2020 metro areas are included: Boston-Worcester-Providence, MA-RI-NH-CT CSA (148), New York-Newark, NY-NJ-CT-PA CSA (408), Bridgeport-Stamford-Norwalk, CT MSA (14860), Hartford-East Hartford-Middletown, CT MSA (25540), New Haven-Milford, CT MSA (35300), Norwich-New London, CT MSA (35980),Worcester, MA-CT MSA (49340), and Torrington, CT MICRO (45860). All eight Connecticut legacy counties are part of one of the six OMB 2020 MSAs and MICROs included in the 2024 database so the entire state of Connecticut is covered in the 2024 database.
Core Based Statistical Areas (CBSAs) are included in the Woods & Poole database. CBSAs are MSAs or MICROs, and CBSA is a collective term for both of these geographies. There are 921 CBSAs in the Woods & Poole database, based on the OMB 2023 definitions, including adjustment made for Connecticut CBSAs.
MSAs, as defined by the OMB, 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. The central cities that form the basis on MSAs and MICROs are generally included in their titles, as well as the name of each state into which the MSA or MICRO extends. MSAs and MICROs are defined in terms of whole counties (or equivalent entities), including in the six New England states. If the specified criteria are met, an MSA 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. MDIVs are not comparable to either MSAs or MICROs, and should not be ranked together.
According to the OMB, if specified criteria are met, adjacent MSAs and MICROs, in various combinations, may become the components of a new set of areas called Combined Statistical Areas. For instance, a CSA may comprise two or more MSAs, a MSA and a MICRO, two or more MICROs, or multiple MSAs and MICROs. In the Woods & Poole database, CSAs are defined in terms of counties. According to the OMB, 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.