Combined Statistical Areas

Combined Statistical Areas (CSAs) consist of two or more adjacent CBSAs that have significant employment interchanges.  The CBSAs that combine to create a CSA retain separate identities within the larger CSAs.  Because CSAs represent groupings of metropolitan and micropolitan statistical areas, they should not be ranked or compared with individual metropolitan and micropolitan statistical areas.

Core Based Statistical Areas (CBSAs) consist of the county or counties or equivalent entities associated with at least one core (urbanized area or urban cluster) of at least 10,000 population, plus adjacent counties having a high degree of social and economic integration with the core as measured through commuting ties with the counties containing the core.  A CBSA receives a category based on the population of the largest urban area within the CBSA.  Categories of CBSAs are: metropolitan statistical areas, based on urbanized areas of 50,000 or more population, and micropolitan statistical areas, based on urban clusters of at least 10,000 population but less than 50,000 population.