The Jamuna River, a major tributary of the Brahmaputra River, presents significant erosion challenges in the Shahjadpur Upazila of Sirajganj District, Bangladesh. This study employs geospatial and statistical methods to map, monitor, and model riverbank erosion in the area from 1988 to 2023. Historical erosion analysis revealed that the period between 1988 and 2003 experienced the highest erosion, with a total area of 25.60 km2 affected. To assess erosion risk, 12 causative factors were identified from the literature and analyzed using Principal Component Analysis (PCA). Slope (40.50%) and distance to river (7.97%) were determined to be the most influential factors. Using a weighted overlay method, erosion risk zones were mapped, revealing that the very high erosion risk zone covers 31.11 km2, primarily impacting Jalalpur, Kaijuri, and Sanatani unions. The high erosion risk zone encompasses 189.37 km2, affecting Porjana, Betail, Khukni, Gala, Rupbati, Habibullahnagar, and Shahjadpur Municipality. Low erosion risk areas are mainly found in Potajia and Kayempur unions. This research fills a critical gap in understanding the dynamics of riverbank erosion and provides policy makers with essential data for evidence-based erosion risk management and mitigation strategies.