A central city area and its surrounding suburbs and small jurisdictions.
Geography defined by the U.S. Office of Management and Budget which includes a city of 50,000 or more inhabitants and the county(s) in which it is located.
An SMSA, defined by the Census Bureau, consists of one or more entire counties containing at least one city (or twin cities) having a population of 50,000 or more plus adjacent counties that are metropolitan and are economically and socially integrated with the central city. In New England, towns and cities rather than counties are the basis for defining an SMSA. SMSA boundaries may cross state lines, as in the case of Washington, D.C.