It heads northwest towards Brockton, passing through Pembroke, Hanson, East Bridgewater and Whitman.

In Sherborn, the road begins a more northerly direction, with a short concurrency with Route 16 in the center of town.

The road heads through the center of Natick, passing the town green and crossing Route 135, which carries the Boston Marathon at that point.

It passes into Maynard, having a short, 0.1-mile concurrency with Route 62 over the Assabet River, before heading north into Acton.

It sweeps by Carlisle before directly crossing into Westford, passing through the southeast corner of town before heading into Chelmsford.