midwestern

from WordNet (r) 3.0 (2006)

midwestern
    adj 1: of a region of the United States generally including
           Ohio; Indiana; Illinois; Iowa; Missouri; Kansas;
           Nebraska; and sometimes Michigan; Wisconsin; Minnesota;
           "a midwestern city"; "midwestern accent"

from The Collaborative International Dictionary of English v.0.48

midwestern \midwestern\ adj.
   Of or pertaining to the Midwest region of the U. S.,
   generally including Ohio; Indiana; Illinois; Iowa; Missouri;
   Kansas; Nebraska; and sometimes Michigan; Wisconsin;
   Minnesota; as, a midwestern city; midwestern accent.
   [WordNet 1.5]