The government has created a new label for these communities, which increasingly fill the gaps on the map between major cities. The new term – Micropolitan Statistical Areas – recognizes that even small places far from metro areas are economic hubs that draw workers and shoppers from miles around. […] The largest micropolitan areas have more people than many metro areas. The Torrington, Conn., micropolitan area is the largest, with a population of 183,000 – bigger than the population of 103 metropolitan areas. Torrington is a micro, not a metro, because the central city has fewer than 50,000 people, the threshold for a city anchoring a metro area. Cities at the centers of micropolitan areas have at least 10,000 people but no more than 49,999.
Source: wiktionary