How can my watershed address help me find USGS data?

(And what is a HUC?)

A watershed address consists of a name and a number (for example, Lower James watershed, 02080206). The 8-digit number is a Hydrologic Unit Code or HUC. The Hydrologic Unit system is a standardized watershed classification system developed by USGS in the mid 1970s. Hydrologic units are watershed boundaries organized in a nested hierarchy by size. They range in size from regions, as shown on the map below, to the smaller cataloging units (HUCs), which are roughly equivalent to your local watershed.

To find your watershed address, follow these steps:

Step 1

Go to the Water Information Network at www.epa.gov (this link opens in a new window).

Step 2

Click on Watershed Questions then click on What is my watershed address? and Locate Your Watershed. Go to Locate by geographic unit (below the map) and search by your zip code, city, county, or tribal nation.

Step 3

Make a note of your watershed name and your 8-digit HUC number--this number is your "password" for finding USGS data in your local watershed.

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