Description: This layer shows 6-digit hydrologic unit code (HUC) boundaries in the northeastern U.S. The 6-digit HUCs contain a nested structure of subwatersheds down to the 12-digit HUC level.
Description: This layer shows 8-digit hydrologic unit code (HUC) boundaries in the northeastern U.S. The 8-digit HUCs contain a nested structure of subwatersheds down to the 12-digit HUC level.
Description: This layer shows 10-digit hydrologic unit code (HUC) boundaries in the northeastern U.S. The 10-digit HUCs contain a nested structure of subwatersheds down to the 12-digit HUC level.
Description: This layer shows 12-digit hydrologic unit code (HUC) boundaries in the northeastern U.S. This is the finest scale of watershed boundaries provided in this map.