Following scholarly research and the official definition by the United States Census Bureau, the American Midwest includes twelve federal states: Iowa (IA), Indiana (IN), Illinois (IL), Kansas (KS), Michigan (MI), Minnesota (MN), Missouri (MO), Nebraska (NE), North Dakota (ND), Ohio (OH), South Dakota (SD), and Wisconsin (WI).
Please click here for all US federal states and respective abbreviations.
The American Midwest

Cartography: Stephan Fuchs
Further Reading
Shortridge, J.R. (1994): Middle West. Its Meaning in American Culture. Lawrence, KS: University Press of Kansas.