Flood susceptibility in the Anambra River watershed was mapped by integrating eight conditioning factors—elevation, slope, height above nearest drainage (HAND), distance to major rivers, drainage density, topographic wetness index (TWI), rainfall, and soil clay content—with the logarithmic percentage change-driven objective weighting (LOPCOW) method. The factors were harmonized to a 30 m WGS 84 / UTM Zone 32N grid and evaluated over 2,010,837 complete-factor cells covering 1,809.7533 km². The LOPCOW weights were highest for slope (20.23%), HAND (16.79%), and elevation (14.29%), followed by river distance (12.28%), clay (11.71%), TWI (10.85%), rainfall (10.41%), and drainage density (3.45%). The weighted index ranged from 0.298647 to 0.890720. Five equal-width classes placed 1.3887 km² in very low, 16.2252 km² in low, 173.8287 km² in moderate, 974.1528 km² in high, and 644.1579 km² in very high susceptibility. High and very high classes together occupy 1,618.3107 km², or 89.42% of the mapped area. The highest class is concentrated in lower terrain close to drainage, with mean elevation of 27.596 m, HAND of 2.802 m, slope of 0.959°, and river distance of 844.742 m. Ward-level summaries identify Abegbu / Iyiora, Enugu-Otu, and Omasi as the portions with the largest high-plus-very-high areas. The resulting maps and tables provide a spatially explicit basis for prioritizing floodplain planning and local drainage assessment in the watershed.