The federal census has identified metropolitan areas since 1960.  The names given to these areas, as well as their boundaries, may change from census to census.  In 1983 they became known as Metropolitan Statistical Areas (MSAs), replacing the earlier Standard Metropolitan Statistical Area (SMSA) designation.  Within a MSA is at least one city with a minimum population of 50,000, or an urbanized area with at least that population.  The total MSA must encompass a minimum of 100,000 inhabitants.
    At the time of the 1990 census Florida had twenty MSAs, compared to eighteen in 1980.  In 1970, however, there were only nine SMSAs, and in 1960 there were seven.  The boundaries of two MSAs, Tallahassee and Tampa-St. Peterburg-Clearwater, were redefined between 1980 and 1990.
The central cities of most Florida MSAs contain less than half of the total population of the MSA.  The city limits of most of these central cities have not changed since they were defined early in this century, and as a result population growth has been mainly in the suburbs.  The Tallahassee MSA is a notable exception, since during the 1980s Tallahassee annexed a large area.