This paper is concerned with a description of the techniques for the development of digital maps of geology and slope instability. The validation of such maps by field inspection and checking is highlighted. These techniques have been used successfully for the suburbs of the northern Wollongong region of New South Wales. Such maps allow the flexibility of future modifications as additional and or more reliable data becomes available. These maps will facilitate decisions on the planning and management of land use. Currently, 295 cases of land instability have been documented within the study area. The maps are also expected to be useful for the development of reliable hazard and risk assessment procedures.