Crevice corrosion was investigated in pure iron exposed to a strong acetate buffer solution. The specimens experienced the potential drop inside the crevice, which resulted in the formation of passive, active, and hydrogen evolution regions. The distribution of hydrogen evolution occurring inside the crevice was mapped using a silver decoration technique applied on the other side of the specimen. The results suggest that the entry of absorbed hydrogen show a variation in the intensity across the crevice. The crevice mouth and bottom portions showed the least hydrogen entry, whereas the intermediate portion yielded the significant amount which resulted in the accumulation of silver deposits.