The Upper 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 Upper Mississippi region, which is listed with a 2-digit hydrologic unit code (HUC) of 07, has an approximate size of , and consists of 14 subregions, which are listed with the 4-digit HUCs 0701 through 0711. In a 1975 report, the region was described as "rich in water - surface water is plentiful, and ground water is a large, important, and manageable resource."
This region includes the drainage of the Mississippi River Basin above the confluence with the Ohio River, excluding the Missouri River Basin. Includes parts of Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, South Dakota, and Wisconsin.
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