The salt content of soils in the principal bauxitic area of the Darling Plateau is broadly known from drilling. Soil salinities averaged over 15 km2 grid blocks bear a strong statistical relationship to a number of easily measured parameters, including distance from the Darling Scarp, mean annual rainfall and drainage density. We have used a nonlinear regression equation (r=0.96) to prepare maps showing soil salinity isopleths estimated with two levels of reliability. Similar regression equations have been used to estimate average soil salt contents over selected depth intervals. These regression equations and maps provide a useful means of estimating average soil salinities in areas where no drilling data are available.