The freeway's northern segment parallels the New Hampshire border, at one point coming as close as 400 feet (120 m) to the boundary, and its southern end is roughly 10 miles (16 km) north of Cape Cod.

I-495 is a heavily traveled route serving communities in Plymouth, Bristol, Norfolk, Worcester, Essex, and Middlesex counties.

The highway comes within two miles (3.2 km) of the Rhode Island state line before turning in a more northerly direction through Franklin and Bellingham.

I-495 passes through Milford, Medway, Hopkinton (where the junction with the Massachusetts Turnpike, or I-90, is located), and Westborough (where the road meets Route 9).

[3][4] Continuing to turn to a more easterly direction, the road passes through Boxborough, Littleton (where there is an intersection with Route 2), Westford and Chelmsford.

It then enters the city of Lawrence, where the road turns due north, crossing the Shawsheen River into North Andover before crossing the Merrimack River at the O'Reilly Bridge back into Lawrence.

The road heads into Haverhill, crossing the Merrimack twice more at a bend in the Bradford section of town.

For much of the stretch between Norton and Milford, the road is within a few miles of Route 140, with two junctions of that highway in Mansfield and Franklin.

[citation needed] In 2014, a new intelligent transportation system was installed to help commuters and the state better understand the traffic congestion on I-495.

[5] Some improvements expected to come to I-495 in the next few years include a project that will install fiber-optic cable, traffic cameras, and variable-message signs on I-495 from I-90 (Hopkinton) to I-93 (Andover).