Amish country

Indiana is the state with the third largest Amish population in the USA; about 50,000, or 1/6 of the total US Amish, live here. Many (more than 1/3) live in LaGrange County, immediately to the east of St. Joseph County. The heart of the Amish country is the triangle spanned by the towns of Elkhart, Shipshewana and Nappanee. (Photo of Shipshewana below from in.gov)

A tour of Amish country makes for an excellent day trip from South Bend. The town of Shipshewana has many lovely craft and quilt stores (the Amish are known for their truly beautiful quilts), particularly in the Davis Mercantile center, and also has a great throwback to older American ways in Yoder's department store. Goshen also has excellent stores, particularly in the Old Bag Factory. Middlebury has good stores too, but probably its main attraction is Das Dutchman Essenhaus, the place to go for cream pies in northern Indiana.  

See here for a map (specifically here). Elkhart, the closest town on this map to Notre Dame, is about a 30 minute drive from Notre Dame.

Warning: If you visit Amish country on Sunday, you will find all stores and restaurants closed.