The Midwestern United States, or the Midwest, is one of the four geographic regions defined by the United States Census Bureau, occupying the northern central part of the country. It was officially named the North Central region by the Census Bureau until 1984.

Though the region is traditionally defined in a number of ways, the Census Bureau's definition consists of 12 states in the north central United States: Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin. Illinois is the most populous of the states and North Dakota the least. A 2012 report from the United States Census put the population of the Midwest at 65,377,684. The Midwest is divided by the Census Bureau into two divisions. The East North Central Division includes Illinois, Indiana, Michigan, Ohio and Wisconsin, all of which are also part of the Great Lakes region. The West North Central Division includes Iowa, Kansas, Minnesota, Missouri, North Dakota, Nebraska, and South Dakota, all of which, except for Iowa, Missouri and Minnesota, are located, at least partly, within the Great Plains region of the country. Major rivers in the region include, from east to west, the Ohio River, the Upper Mississippi River, and the Missouri River.