Floods have become more severe, and climate change and human-driven land-use changes are intensifying flooding, straining river channels, and altering structures more frequently. Flood risk assessment involves comprehensive strategies for protecting lives and aims at minimizing the impact of floods on the economy, communities, and environment. This process typically includes assessing topography, geography, hydrological patterns, community input, climate trends, and historical flood data for accurate forecasting, and employing mapping technology to identify vulnerable zones. This study focused on evaluating flood risk and identifying inundation-prone areas within Kokrajhar District, located in the flood-affected region of Northeast India. To determine the factors contributing to flooding, the analysis utilized data related to soil characteristics, topographic slope, contour lines, elevation, drainage density, and land-use patterns. This paper deals with determining the highest flood level in the Gaurang River basin using the synthetic unit hydrograph (SUH) method to analyze flood risk management in Kokrajhar district, Assam. Utilization of synthetic unit hydrograph incorporating geomorphic parameters extracted using geographic information system (GIS) for generation of flood hydrographs, with emphasis on ungauged and partially gauged catchments. A flood risk management study in Kokrajhar district is crucial for safeguarding lives, property, and the environment. Consequently, flood forecasting, early warning systems, and management strategies are carried out routinely and in a sustainable manner.