Using the settled areas of South Australia as a case study, this paper seeks to demonstrate the specific importance of rural population and settlement density as an important variable in understanding the social, population and settlement geography of sparsely settled rural regions, where sparse and falling density presents both practical and conceptual problems for rural planners. After a review of the literature on population density, the case is argued for the use of net rural rather than gross density in the analysis of settlement patterns. The paper then tests a series of hypotheses on the empirical relationship between rural density as independent variable and selected demographic and socio-economic indicators as dependent variables, at two specific points in time. For the same region, points in time and set of indicators, it goes on to compare the predictive power of rural density as an independent variable with that of three other important qualities of rural settlement patterns (remoteness, settlement size and urban concentration). Rural density is found to be a significant explanatory variable, both in its own right and in comparison with the three other variables tested. In conclusion, the findings are related to policy development measures for rural Australia. (C) 2002 Elsevier Science Ltd. All rights reserved.