Its southern terminus within the state is located in Attleboro, where I-95 enters from Pawtucket, Rhode Island.

At this interchange, I-95 begins running concurrently with US 1 and Route 128 along a beltway roughly 15 miles (24 km) outside of Boston.

As such, Boston is one of only two major east coast cities that I-95 bypasses (the other, Washington DC, for the same reason).

Mansfield is home to the Xfinity Center, a Live Nation Entertainment-owned amphitheater that hosts numerous concert events, and TPC Boston, a PGA Tour player's club that hosted the Dell Technologies Championship yearly.

As the Interstate continues through Sharon, it then enters Greater Boston and the towns of Walpole, and Norwood, before entering Canton, where it meets I-93 at its southern terminus, and I-93 continues as exit 26 (old exit 12) to the right of I-95, while I-95 traffic is routed in a single lane to a sharp clockwise curve where it meets US 1 in a wrong-way concurrency.

Upon interchanging with I-93, I-95 loops around to the west, taking over the roadbed from I-93 (now four lanes) and joining US 1 southbound in a wrong-way concurrency.

The highway enters Westwood next, with US 1 leaving the freeway near the Dedham town line to parallel I-95 back to the south.

Then, the highway passes through Newton, then enters Weston and has a large interchange with the Massachusetts Turnpike (I-90) that provides connections to nearby Route 30.

I-95 and Route 128 are due west of Boston at this point and begin to turn to the northeast, serving the city of Waltham and the town of Lexington along the way.

After leaving Route 128, I-95 expands back to six lanes and then to eight lanes at the partial interchange with US 1 (exit 66, old exit 46) about one mile (1.6 km) north of Route 128 and heads north through the less densely populated northeastern portion of the state.

This is a list of rest areas on I-95 in Massachusetts:[3] Weigh stations are located on the northbound and southbound sides of the highway at the following locations:[4][better source needed][5] Between the Rhode Island state line and I-93 in Canton, and again between the northern end of the beltway and the New Hampshire state line, the speed limit is 65 mph (105 km/h).

[citation needed] The sharp transition curve from I-95 north onto the Route 128 beltway in Canton is posted for 25 mph (40 km/h).

The highway would have progressed from Route 128 and Readville, followed the Southwest Corridor, ran along Melnea Cass Boulevard in Roxbury, heading east, and joining the Southeast Expressway at South Bay, then north to the Central Artery at the South Station interchange with the Massachusetts Turnpike/I-90, and connecting with the Northeast Expressway at the Charlestown banks of the Charles River.

However, due to pressure from local residents, all proposed Interstate Highways within Route 128 were canceled in 1972 by Governor Francis Sargent with the exception of I-93 to Boston.