The Dorchester-Milton Lower Mills Industrial District is an historic district on both sides of the Neponset River in the Dorchester area of Boston and in the town of Milton, Massachusetts. It encompasses an industrial factory complex, most of which was historically associated with the Walter Baker & Company, the first major maker of chocolate products in the United States. The industrial buildings of the district (now in mixed industrial/retail/residential use) were built between about 1868 and 1947, and were listed on the National Register of Historic Places in 1980, with a slight enlargement in 2001.