The term was created by author G. Scott Thomas for a 1989 article in American Demographics magazine, and was expanded in his 1990 book, The Rating Guide to Life in America's Small Cities. It gained currency in the 1990s to describe growing population centers in the United States that are removed from larger cities, in some cases 100 miles (160 km) or more. Lower land and labor costs have led to many housing subdivisions and suburban cultures similar to those found in larger metropolitan areas developing in and around the micropolitan areas.
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 town's population and not on that of the whole area, some micropolitan areas are actually larger than some metropolitan areas. The largest of the areas, the one whose core city is Torrington, Connecticut, had a population in excess of 180,000 in 2000; Torrington's population in that year's census was only 35,202.
Many such areas have dynamic rates of growth; however, all micropolitan areas combined account for about 10% of the population.