Many scholars agree that there is no clear consensus regarding what “urban sprawl” is or what causes it. The term “sprawl” can be used or defined a number of ways for many situations. When its definition is ambiguous, it is impossible to determine its causes or consequences, including the effects of any policies designed to contain it. In this paper, first, we provide a conceptual definition of urban sprawl based on different dimensions such as density, concentration, proximity to services, automobile dependency, and extent of vegetation cover being paddy, eco-sensitive, or with decreased plantation areas. Such a definition provides a basis for understanding urban sprawl, its nature and its characteristics being location and context specific. Second, an “extended urban area” is demarcated as the geographical base for the study of the urban sprawl. Each dimension is defined and tested in 25 urbanized and suburbanized areas in the Colombo Metropolitan.