The Middlesex Turnpike was an early turnpike between Cambridge and Tyngsborough, Massachusetts and the New Hampshire border, where it connected with the Amherst Turnpike and thence Nashua and Claremont, New Hampshire.
The turnpike was chartered on June 15, 1805, by the Massachusetts legislature. After an extremely contentious argument about its route, it opened about five years later. The road started near present-day Technology Square in East Cambridge, where it intersected with the Cambridge and Concord Turnpike (now Broadway), headed roughly northwest along what are now Hampshire and Beacon Streets, passed by the 'Foot of the Rocks' in West Cambridge (now along Massachusetts Avenue in Arlington), and onwards to Lexington by today's Westminster and Lowell Streets. From there, it continued through Burlington, Bedford, and Billerica, the section of which is still called the Middlesex Turnpike as far as Concord Road in Billerica. The remainder of the right of way in Billerica is fragmented. The portion between Concord Road and the Concord River had become overgrown with fairly substantial trees, but a portion was recently recleared and paved as a driveway into a new commercial development that is not yet completed. On the north side of the Concord river, short section now called Old Middlesex Turnpike serves a few blocks in a residential neighborhood, but a gate blocks access to the block nearest the river. The section between River Street Extension and River Street is substantially overgrown, with the southern end serving as a dirt driveway from River Street into a couple residences. The portion of River Street nearest U.S. Route 3 also follows the original right of way. There are original fragments remaining in the Billerica State Forest, alongside Route 3, and again north and south of Rangeway Road. From Billierca, it continued northwest to Chelmsford, and then along the bank of the Merrimack River to Tyngsborough. A small, 1.5-mile (2.4 km) stretch of the turnpike remains in Chelmsford, now known as "Turnpike Road." There is also a short residential street named "Old Middlesex Turnpike Street" that lies on or very near the original right-of-way, and the occasional property line denotes the original route. From there, maps show a route through Chelmsford along North Road and Princeton Street into what is now North Chelmsford's Vinal Square, then along Tyngsboro Road through North Chelmsford and Middlesex Road through Tyngsboro to Nashua, New Hampshire. It was about 26 miles (42 km) in length, with four (4) toll gates along the way.
As was the practice of that time, the road was as straight as possible, and thus missed the advantages of passing through economic centers along the way. As its route closely paralleled that of the Middlesex Canal, and later the railroad, it suffered stiff competition for both freight and passenger traffic. The road was thus never particularly profitable. Its charter was repealed in 1841, and it became a free road in 1846. Some sections became disused at some point - there is a section in Billerica at the Concord River that is discontinuous, and a large section missing between Billerica (River Street) and Chelmsford (Mill Road).
U.S. Route 3, the expressway largely built in the 1950s from Burlington to Tyngsboro, is substantially parallel to the Middlesex Turnpike.
The MassDOT is upgrading the Middlesex Turnpike in cooperation with the Towns of Burlington, Bedford and Billerica. Phase 2 which began in Burlington at Route 62 and Middlesex Turnpike and stretches into Bedford just north of Crosby Drive. Phase 1 was Completed in 2007. Total cost of Phase 2 was expected to be $13 Million+. Construction on Phase 2 was expected to begin in July 2010. The contractor for Phase 2 is Newport Construction Corporation of Nashua New Hampshire. With the completion of Phase 2, the main flow of traffic will use a new road named Network Drive to bypass a "thickly settled" (residential) section of the Middlesex Turnpike located between Terrace Hall Road and the Bedford line in Burlington.
Billerica is planning that phase 3 become a multi-modal corridor—a green road plus 3 modes, including transit, bike lanes and sidewalks for pedestrians.