Exurb

An exurb (also known as a bedroom community and as a commuter town) is a municipal (often urban area) within a larger metropolitan area, lying beyond the suburbs, that is separated from the principal city by rural territory.

Examples

Principal City	Exurbs
Chicago, Illinois, USA	DeKalb, Kankakee
London, UK	Milton Keynes, St. Albans
San Francisco or San Jose, California, USA	Tracy, Modesto

References

Demographia| Definition of Urban Terms. (n.d.). Retrieved from http://www.demographia.com/db-define.pdf