There's always Roanoke in Virginia. Although Virginia isn't part of the Midwestern states, the city of Roanoke definitely suits the bill in terms of both population (ca 100,000+), and overall look and location. It's a medium-sized typical American city located right next to the Blue Ridge Mountains). It even has a river flowing through the city, and their police department is also fittingly called the RPD.
Based on look alone, both the city and the mountain range located to the northwest is eerie similar to Raccoon City and the Arklay Mountains seen in the original trilogy.
And on a funny sidenote, Roanoke is commonly referred to as "Star City" which would be a reference to S.T.A.R.S.