Massachusetts Route 40
Route 40 is a east-west state route located in northeastern Massachusetts, entirely within Middlesex County. The short highway connects Groton and Chelmsford. Its western end is at an intersection with Massachusetts Route 119 and Massachusetts Route 225 in Groton, and its eastern end is at Route 3A in North Chelmsford. The route has existed since the late 1940s.
U.S. Route 3 has an interchange with Route 40, at exit 33.