The Federal Trade Commission required the discount retailer to sell the locations to maintain competition for consumers after the $9.2 billion deal closes, the agency said in a statement on Thursday.
"This settlement will ensure that consumers will continue to benefit from competition among their local dollar stores," said Debbie Feinstein, director of the commission's competition bureau.
Family Dollar's investors approved the transaction in January after a six-month saga that featured a higher offer from Dollar General. The takeover creates the largest U.S. dollar-store chain.
While Dollar Tree had said its bid would more easily clear antitrust hurdles, the completion date was delayed multiple times as the retailer worked with regulators. Dollar Tree expects to close the purchase early this month.
Under the terms of the Dollar Tree deal, Family Dollar locations will keep their name.
