Lower Mississippi water resource region

The Lower Mississippi 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 Lower Mississippi region, which is listed with a 2-digit hydrologic unit code (HUC) of 08, has an approximate size of 106,741 sqmi, and consists of 9 subregions, which are listed with the 4-digit HUCs 0801 through 0809.

This region includes the drainage within the United States of: (a) the Mississippi River below its confluence with the Ohio River, excluding the Arkansas, Red, and White River basins above the points of highest backwater effect of the Mississippi River in those basins; and (b) coastal streams that ultimately discharge into the Gulf of Mexico from the Pearl River Basin boundary to the Sabine River and Sabine Lake drainage boundary. Includes parts of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee.