The Alaska water resource region is one of 21 major geographic areas, or regions, in the first level of classification used by the United States Geological Survey to divide and sub-divide the United States into successively smaller hydrologic units. These geographic areas contain either the drainage area of a major river, or the combined drainage areas of a series of rivers.[1][2]
The Alaska region, which is listed with a 2-digit hydrologic unit code (HUC) of 19, has an approximate size of 720,535 square miles (1,866,180 square kilometers), and consists of 6 subregions, which are listed with the 4-digit HUCs 1901 through 1906.[3]
This region includes the drainage within the state of Alaska. Includes all of Alaska.[3]