The Great Midwest Commonwealth or Midwest Commonwealth was one of the thirteen commonwealths of the pre-war United States of America. Created in the early 21st century, it was comprised of the former states of Wisconsin, Minnesota, Illinois, Indiana and Michigan.
The Illinois Wasteland was conquered by Brotherhood of Steel deserters known as the Midwestern Brotherhood. They led a harsh rule on the state. An Enclave outpost is also said to be located in the boundaries of Chicago.