South Attleboro is a neighborhood of Attleboro, a city in Bristol County, Massachusetts, United States. It is perhaps best known for the South Attleboro station on the Attleboro/Stoughton Line of the MBTA Commuter Rail. U.S. 1 (the old Norfolk and Bristol Turnpike) and Route 1A (the old Lower Boston Post Road) pass through the area, which lies just north of the Rhode Island state line.