This thesis presents an analysis of data from Japan's 2020 national census, estimating population and households in disaster-prone regions. These regions include flood-risk areas, tsunami-vulnerable zones, and sediment disaster areas. In Level 2 flood risk areas, around 50.4 million people reside, with nearly half in multi-unit housing and 28% living above flood depths. Approximately 8.2 million people inhabit tsunami-prone areas, and 5.3 million people live in sediment disaster hazard zones. Major cities in disaster-prone areas have a large population, but a significant portion of residents resides in multi-unit housing, which doesn't always correlate directly with higher disaster risks.