Why do some ZCTAs ending in “HH” contain land area?
After Census 2000, efforts to improve the spatial accuracy of the TIGER database have and continue to add land area such as small islands or sections of shoreline to census blocks that were entirely water in Census 2000. Census 2000 tabulation census blocks once consisting entirely of water features may now contain a mix of water and small land features. As a result, “HH” ZCTA codes may no longer represent purely water areas.
