From 1969 until 1987, the eastern terminus of Route 25 was at a junction with Maple Springs Road, US 6 and Route 28 in Wareham near the modern location of Exit 2. The MassDPW and the Massachusetts Highway Department (MassHighway) had plans to extend the freeway eastward to Cape Cod as early as 1953, when the route was included in the proposed Cape Cod Expressway that would connect New York City with Cape Cod. Route 25 was originally planned to connect to the Sagamore Bridge, which carried US 6 over the Cape Cod Canal and was used to access the towns of Hyannis and Provincetown. In 1962, however, the MassDPW conducted traffic studies on the two bridges crossing the canal and found that the Sagamore Bridge was above vehicular capacity, whereas the more southern Bourne Bridge had excess capacity. The Route 25 freeway was then redesigned to cross over the Bourne Bridge and connect with the Mid-Cape Highway (US 6) on the southern side of the canal via the proposed Southside Connector. The connector would have been constructed through the Massachusetts Military Reservation in Bourne, but was canceled by the MassDPW and MassHighway in 1977 when environmental tests indicated the freeway would disturb underground aquifers serving as water sources for the region. MassDPW instead changed the proposed eastern terminus of the Route 25 expressway to the approach ramps of the Bourne Bridge.