MSA is the acronym for Metropolitan Statistical Area. The MSA is the formal definition of a region that consists of a city and surrounding communities that are linked by social and economic factors. MSA’s are 5-digit codes of 306 high population-density geographic areas that are delineated by the U.S. Office of Management & Budget.

MSA are used for a variety of purposes for collecting, tabulating, and publishing federal statistics. It is an economically and socially integrated unit consisting of one or more contiguous counties (or statistically equivalent areas) containing at least one city of a population of 50,000 or more, and a metropolitan population of 100,000 or more (75,000 in New England).