Ohio water resource region

The Ohio 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.

The Ohio region, which is listed with a 2-digit hydrologic unit code (HUC) of 05, has an approximate size of 162,916 sqmi, and consists of 14 subregions, which are listed with the 4-digit HUCs 0501 through 0514.

This region includes the drainage of the Ohio River Basin, excluding the Tennessee River Basin. Includes parts of Illinois, Indiana, Kentucky, Maryland, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia.