This dataset presents historic flood levels marked on buildings and other structures in the Rhine river delta. These flood marks provide maximum water levels across the region from the late sixteenth to late twentieth centuries, complementing instrumental measurement records in both space and time. Besides the locations (RD, spatial accuracy ~1 m) and elevations (NAP, vertical accuracy ~0.03 m), the dataset provides the epigraphic inscriptions of the marks and relevant information (type, age) on the constructions holding the marks. In total, the inventory contains 131 flood marks from 46 locations spread across 32 towns. The data provide tangible evidence of historic flood events and are useful in quantitative analyses of past flood patterns and magnitudes in the Rhine river delta.