Federated will expand its MainStreet division.

The company said four stores will be opened in the Detroit area next fall, with six to eight others planned for later. This marks MainStreet’s first expansion outside the Chicago area, where in 14 months it has grown to nine stores, with two more planned for next spring. Federated intends eventually to open stores nationwide. A Federated spokeswoman said the stores, which carry apparel and home textiles for middle-income customers, compete primarily with Sears, J. C. Penney and Mervyn’s.