This study is concerned with the rural-urban fringe as a complex transition zone on the periphery of growing urban areas in Western countries. Case studies of the fringe and related areas are reviewed, and a definition of the rural-urban fringe is suggested. Further, the urban fringe is differentiated from the rural fringe, the former constituting the subzone of most rapid exurban invasion. Hypotheses are postulated regarding the residents, accessibility, and land and dwellings in the fringe, and suggestions for future studies are outlined in the conclusion.