Live Map Services EPA Office of Water (OW): NHDPlus v21+AK Beta WBD Hydrologic Units - Twelve-Digit Subwatersheds
This dataset contains twelve-digit hydrologic subwatershed units from the Watershed Boundary Dataset derived from NHDPlus v2.1 for the contiguous United States, Hawaii, Puerto Rico, the US Virgin Islands, Guam, American Samoa and the Northern Mariana Isla...