Introduction: Several studies have supported the role of public transport in encouraging active transport through commuting. Investigating actual increases in public transport use within focussed local areas can help unravel what causes such increases. Methods: In this study, we investigated factors related to the increase in public transport use in focussed local areas (hotspots) through a geospatial mixed-method approach using data from South Western Sydney, Australia, spatial cluster detection, and local stakeholder interviews. We also examined areas with low levels of public transport use. Results: We found that while distance to train station is a significant predictor of usage, other important factors include the professional and socioeconomic profile of the neighbourhood around the train station, the train line's deemed attractiveness and parking availability. Conclusions: Thus, researchers and planners must consider a range of built environment factors when planning for changes that encourage public transport use. In addition, focusing on small local areas utilising geospatial mixed methods can provide important insights into the local drivers of public transport use.