A Metropolitan Statistical Area is an urban centered geographic area with a population of at least 50,000 people defined for the U.S. Census Bureau to collect, organize and analyze data and statistics.
A metropolitan statistical area, or MSA, is at lease one county centered by at least one urban core with surrounding communities and counties that are economically and socially dependent upon that population center.
In real estate, metropolitan statistical area was shortened to MSA, however, this could lead to confusion since the counterpart to a metropolitan statistical area is the micropolitan statistical area which differs only population size.
Surrounding communities and counties can be included in the metropolitan statistical area based on their relationship to the population center as indicated by employment and the commuting trends of the population.
A metropolitan statistical area is one of two subcategories of core based statistical areas. The other is a micropolitan statistical area which is the same as a metropolitan statistical area except it has a population size between 10,000 and 50,000 people.
Multiple metropolitan and micropolitan statistical areas can be combined into combined statistical areas (CSAs) if they are substantially interdependent on employment.
An example metropolitan statistical area would be the Los Angeles - Long Beach - Anaheim, CA metropolitan statistical area that consists of Los Angeles and Orange counties.
The Los Angeles - Long Beach - Anaheim metropolitan statistical area largely exceeds 50,000 people. It has multiple interdependent urban population centers that are highly interconnected through employment and commuting driven by the Los Angeles urban core and surrounding communities.
The U.S. Census Bureau publishes numerous publications and resources based on metropolitan and micropilitan statistical areas.