Map of eastern Massachusetts with Route 126 highlighted in red
|Length||33.5704 mi (54.0263 km)|
|South end||Route 126 in Woonsocket, RI|
|North end||Route 2 / Route 2A in Concord|
|Counties||Worcester, Norfolk, Middlesex|
Route 126 begins at the Rhode Island state line, continuing into Woonsocket as Rhode Island Route 126. After a short stretch in the town of Blackstone and Worcester County, Route 126 enters the town of Bellingham and Norfolk County, heading north. In Bellingham, Route 126 has a short concurrency with Route 140 at the center of town. In the north of the town, the route turns east on Hartford Avenue, crossing I-495 at Exit 18. Shortly after entering the town of Medway, the route turns north again, crossing Route 109 shortly after that. Route 126 then enters Holliston, in Middlesex County.
In Holliston, Route 126 shares a 2.3 miles (3.7 km) long concurrency with Route 16 through the center of town. After splitting from Route 16, Route 126 heads north into Ashland, passing through the eastern side of town before entering Framingham. The route passes Waushakam Pond before crossing Route 135 near the center of town, next to the Framingham MBTA station. The road bears to the right, passing Gleason Pond before crossing over Route 9 with exit ramps between the two. At this point, Route 30 eastbound joins Route 126 for a short stretch before meeting Route 30 westbound. Route 126 continues northward, crossing the Massachusetts Turnpike (I-90) without junction. (The nearest exit along the Pike is on Route 30 to the east.)
As it passes Lake Cochituate, Route 126 enters the town of Wayland. The route then joins Route 27 for a mile, crossing U.S. Route 20 together just before the two routes split. Route 126 then enters the town of Lincoln. After crossing Route 117, the route continues north, crossing the Fitchburg Line before entering Concord. As the route rounds the banks of Walden Pond through the State Reservation, it finally ends at Routes 2 and 2A next to Concord-Carlisle Regional High School.
|Worcester||Blackstone||0.00||0.00||Route 126 south||Continuation into Rhode Island|
|Norfolk||Bellingham||5.4||8.7||Route 140||Short, 90-yard concurrency with Route 140.|
|7.664||12.334||I‑495||I-495 Exit 18.|
|Middlesex||Holliston||12.9||20.8||Route 16 west||Western terminus of concurrency with Route 16|
|15.2||24.5||Route 16 east||Eastern terminus of concurrency with Route 16|
|Framingham||20.0||32.2||Route 135||Crossing point for the Boston Marathon.|
|21.6||34.8||Route 9 / Route 30 west||Route 30 Eastbound ends its concurrency Route 9 and begins one with Route 126.|
|21.8||35.1||Route 30 east||Western terminus of concurrency between Route 30 Eastbound and Route 126.|
To I‑90 (Mass Pike) via Route 30 Eastbound.
|22.9||36.9||I‑90 (Mass Pike)||No direct access between I-90 and Route 126. (Access is available via Cochituate Road.)|
|Wayland||26.3||42.3||Route 27 south||Southern terminus of concurrency with Route 27.|
|27.4||44.1||Route 27 north||Northern end of concurrency with Route 27.|
|Concord||33.57||54.03||Route 2 / Route 2A||Northern end of Route 126; Walden Street continues north to Route 62.|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|