Exurban-style density along the Pennsylvania-Maryland-Delaware border, part of Philadelphia metropolitan area. There is continuous exurban development from north of Boston to south of Richmond, Virginia, in the Northeast megalopolis
Exurban development (left side) blends into suburban development (right side) in Loudoun County, Virginia, in the western part of the Baltimore–Washington metropolitan area

An exurb is an area outside the typically denser inner suburban area of a metropolitan area, which has an economic and commuting connection to the metro area, low housing density, and growth. It shapes an interface between urban and rural landscapes holding an urban nature for its functional, economic and social interaction with the urban center, due to its dominant residential character.[1] Confusingly, the term "exurb" was used starting in the 1950s as a synonym for a commuter town, as the word "exurb" (a portmanteau of "extra & urban") was coined by Auguste Comte Spectorsky, in his 1955 book The Exurbanites, to describe the ring of prosperous communities beyond the suburbs that are commuter towns for an urban area.[2] However, especially since a landmark report[citation needed] by the Brookings Institution in 2006, the term is generally used for areas beyond suburbs and specifically less densely built than the suburbs to which the exurbs' residents commute.[3]


According to the Brookings Institution (2006), to qualify as exurban, a census tract must meet all three of the criteria described below.[3]

  1. Economic connection to a large metropolis.
  2. Low housing density: bottom third of census tracts with regard to housing density. In 2000, this was a minimum of 2.6 acres (11,000 m2) per resident.
  3. Population growth exceeding the average for its metropolitan area.

Exurban areas incorporate a mix of rural development (e.g., farms and open space) and in places, suburban-style development (e.g., tracts of single-family homes, though usually on large lots). In long-settled areas, such as the U.S. Northeast megalopolis, exurban areas incorporate pre-existing towns, villages and smaller cities, as well as strips of older single-family homes built along pre-existing roads that connected the older population centers of what was once a rural area.

Exurban counties in the United StatesEdit

In a 2006 study, the Brookings Institution identified the following as exurban counties, defined as having at least 20% of their residents in exurban Census tracts:[3]


  1. ^ Caves, R. W. (2004). Encyclopedia of the City. Routledge. p. 254.
  2. ^ Spectorsky, Auguste C. (1955). The Exurbanites. Lippincott, Philadelphia: J. B. Lippincott & Co. OCLC 476943.
  3. ^ a b c Berube, Alan; Singer, Audrey; Wilson, Jill H.; Frey, William H. (October 2006). "Finding Exurbia: America's Fast-Growing Communities at the Metropolitan Fringe". Living Cities Census Series. Washington, D.C.: The Brookings Institution. Retrieved 2020-08-03. We first identify exurbs using census tracts—small areas with an average of 4,000 people—and then aggregate these areas to the county level for further analysis.