Hydrologic Unit Boundaries
Hydrologic unit boundaries at the 2-digit (Water Resource Region), 4-digit (Subregion), 6-digit (Accounting Unit) and 8-digit (Cataloging Unit) level are shown in different colors and line thicknesses.
Cautions for this Product:
Aggregate Layer: 8 Digit Hydrologic Units
Other Layers Displayed: 6 Digit Hydrologic Units, 4 Digit Hydrologic Units, 2 Digit Hydrologic Units
A hierarchical system developed by the U.S. Geological Survey that divides the United States and the Caribbean into 21 major regions, 222 subregions, 352 accounting units, and further subdivided into 2,150 cataloging units that delineate river basins having drainage areas usually greater than 700 square miles. [USGS]
Product ID: 2143
Production Date: 7/18/97
Product Type: Map
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