No. Counties 7 (15 in Greater Michiana) States Indiana, Michigan Postal Codes 46-49 Largest City South Bend Second Largest City Elkhart Time Zones Eastern, Central US Region Midwest Michiana is a region in northern Indiana and southwestern Michigan centered on the city of South Bend, Indiana. The Chamber of Commerce of St. Joseph County, Indiana defines Michiana as "counties that contribute at least 500 inbound commuting workers to St. Joseph County daily." Those counties include… (More on Michiana)