The recent high death tolls caused by large earthquakes are a further indication that earthquakes remain one of the most destructive natural disasters in the world and can seriously threaten the achievement of sustainable development goals. To effectively reduce the existing seismic risk, the limited available mitigation resources should be allocated to areas where the potential risk is most severe. However, such areas are typically uncertain and difficult to locate. Here, we propose a strategy to delineate regional high seismic risk zones at a fine resolution and with high confidence. Our analyses reveal that the delineated zone accounts for only ~7% of the regional land area but for ~85% of the total financial loss. We recommend that seismic risk mitigation measures be prioritized in such high-risk zones, especially for densely populated cities in seismically active areas, to better meet the disaster risk reduction targets in the Sendai Framework.