Hydrology Data

From the regional level down to the watershed

Source: USGS

A hydrologic unit code is a sequence of numbers or letters that identify a hydrological feature like a river, stream, snow covered area, or a watershed (also called a drainage basin). The USGS maintains a hierarchical system of hydrologic units broken up into regions, sub-regions, accounting units, and cataloging units. Each hydrological area has its own Hydrologic Unit Code (HUC). View hydrology reports by HUC code to get a closer look at river and snow conditions across the US.

Name Level Digits Avg Sq Miles # of Areas
Region 1 2 177,560 21
Subregion 2 4 16,800 222
Basin 3 6 10,596 370
Watershed 4 8 700 2,200

Hydrology Heatmap

Click on any region to learn more. Right click to zoom out.

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