An area designated by the United States Geological Survey as belonging to a certain watershed.
The United States is divided and sub-divided into successively smaller hydrologic units which are classified into four levels: regions, sub-regions, accounting units, and cataloging units. The hydrologic units are arranged within each other, from the smallest (cataloging units) to the largest (regions). Each hydrologic unit is identified by a unique hydrologic unit code (HUC) consisting of two to eight digits based on the four levels of classification in the hydrologic unit system. For more information see the USGS Water Resources Web site.
an eight-digit code used to catalog watersheds.
The 8-character federal code identifying the Cataloguing Unit, the smallest of the different hydrologic units. The coding is hierarchical with a 2-character region, a 4-character subregion, a 6-character accounting unit and an 8-character cataloguing unit.
Hydrologic units are geographic areas representing part or all of a surface drainage basin or distinct hydrologic feature and are delineated on the State Hydrologic Unit Maps. Each hydrologic unit is identified by a unique number (HUC), and a name.
a hierarchical classification of drainage basins. An 8 digit HUC indicates region (leftmost 2 digits), sub-region (next two digits), accounting unit (next 2 digits), and cataloging unit (rightmost 2 digits). The Snake River basin is entirely within the Pacific Northwest Region (17).
