The hydrogeology of the Lachlan Catchment has been studied by numerous authors over the past 40 years, but there are still many gaps in our understanding of the groundwater systems and river-aquifer interactions. These shortfalls in our knowledge limit our capacity to manage water resources throughout the catchment. This document captures our current understanding of the hydrogeology of the catchment and provides a multidimensional spatial analysis of the groundwater monitoring bore standing water level (SWL) data. Based on the findings, recommendations for further research are presented