United States micropolitan statistical areas (µSA, where the initial Greek letter mu represents "micro-"), as defined by the Office of Management and Budget (OMB), are labor market areas in the United States centered on an urban cluster (urban area) with a population of at least 10,000 but fewer than 50,000 people. The micropolitan area designation was created in 2003. Like the better-known Metropolitan Statistical Areas, a micropolitan area is a geographic entity used for statistical purposes based on counties and county equivalents. The OMB has identified 536 micropolitan areas in the United States.
The term "micropolitan" gained currency in the 1990s to describe growing population centers in the United States that are removed from larger cities, in some cases by 100 miles (160 km) or more.
Micropolitan cities do not have the economic or political importance of large cities, but are nevertheless significant centers of population and production, drawing workers and shoppers from a wide local area. Because the designation is based on the core urban cluster's population and not on that of the whole area, some micropolitan areas are actually larger than some metropolitan areas. For example, the Ottawa-Peru, IL Micropolitan Statistical Area had a 2010 census population of 154,908. That would put its total population ahead of roughly 100 individual locations classified as a Metropolitan Statistical Area in 2010. The largest of the areas, around Claremont and Lebanon, New Hampshire, had a population in excess of 218,000 in 2010; Claremont's population was only 13,355 in that year's census, and Lebanon's population was only 13,151.