A notable piece of construction was the road of the "Second Massachusetts," chartered March 8, 1797, to build "from the west line of Charlemont, in the county of Hampshire, to the west foot of Hoosuck Mountain in Adams, in the county of Berkshire." This road was the predecessor of the Hoosac Tunnel, following closely the same route. It followed up the valley of the Deerfield River on the southerly bank as far as Buckley Brook, near the present Hoosac Tunnel station. Then bearing southerly it described a semicircular course up the east side of the mountain, and so on to North Adams. That the project was long in maturing is shown by the finding of a plan dated 1795 in the Massachusetts archives, on which the route of the proposed turnpike is shown. In 1804 the company was authorized to build a bridge over the Deerfield River at the easterly end of its turnpike. They must have been long in availing themselves of this privilege, for not until 1817 were they allowed to erect a gate on the bridge. An unobstructed bridge at the far end of the road must have been extensively and freely used, and it is not to be expected that the company waited long under such circumstances before applying for relief. An instance of how closely the corporation was held to the privileges contained in the act of incorporation is found in 1830, when, by special act, David White of Heath was authorized to call a meeting of the proprietors "for the purpose of choosing a clerk," and nothing else. Evidently the corporation had lost its clerk, by death or otherwise, and by no other person could the stock holders be called together; and only at a meeting called by a duly elected clerk could any business be transacted. That the receipts did not yield sufficient revenue can be seen from an act passed in 1817, in which the company is allowed to erect an additional gate, which meant one more collection of tolls, while the rates of toll were slightly increased also. In 1833 the corporation was dissolved and the road made free.

This route over Hoosac, or Florida, Mountain followed approximately the line of the old Mohawk Trail, over which those dusky warriors proceeded in 1664 on their terrifying raid, which resulted in the extermination of the Pocumtuck tribe, which lived in the Connecticut Valley. In 1914 the Massachusetts Highway Commission completed the construction of a state highway over nearly the same line, and the route, originally blazed in savage vengeance and hatred, has now become one of the most popular and beautiful roads of the country. At the highest point, where the road crosses the backbone of the old Bay State, and for two miles easterly from it, the Mohawk Trail, as the new state highway is called, is on the line of the old Second Massachusetts Turnpike.

The Second Massachusetts was a route for several of the stages from Boston to Albany, which continued on the Williamstown Turnpike to Williamstown, and then followed up the valley of the Green River and the West Branch to Hancock Center.