AMP: 17
Location: North Rd and Northwest Expy, Chelmsford
After the US 3 junction, stay straight to follow Route 4 north to Route 3A.
AMP: 18
Location: North Rd and Princeton St, Chelmsford
Soon thereafter, we’ll approach Route 3A.
AMP: 18
Location: North Rd and Princeton St, Chelmsford
Turn right for 3A south to Lowell. Follow 3A north to Tyngsboro.
AMP: 18
Location: North Rd and Princeton St, Chelmsford
Stay straight for 3A north. Turn right for 3A south. Route 4 ends.
N to MA 40, S to MA 110
