Population density × median age from the 2020 census — density from all 8 million inhabited census blocks, color by the median age of each block group. Click anywhere for the exact age pyramid (DHC P12).
Notes. Density is exact block-level census truth (POP20 / land area); median age comes from each block group's P12 table (5-year bands, interpolated; ~240,000 block groups). Alaska west of the antimeridian is clipped. Popups show exact counted pyramids — this is the same data quality as the Japan map.