Recently, radar rainfall data have emerged as an alternative to in situ observations due to their availability over vast ungauged regions. The focus of this study is to integrate the available radar products within a distributed hydrologic model to characterize the spatial extent of flooding. We present a methodology based entirely on radar rainfall data to set up and calibrate a hydrologic model, simulate the spatial extent of flooding. This study used a two-dimensional hydrologic model for the simulation of extreme flood events that occurred in the Linbain River watershed during Typhoon Morakt, 2009. The analysis showed the value of integrating radar precipitation data along with space-based flood inundation extents as inputs to the distributed hydrologic model. Results show that the quantification of flooding spatial extent with radar data can help to calibrate and evaluate hydrologic models and, hence, potentially improve flood inundation prediction and flood management strategies in the catchments.