Highway 115 was a new highway constructed in the mid-1950s and gradually improved over the following 40 years. Initially, the route was constructed as a two-lane connection from Highway 35 near
Pontypool to Highway 28 on the outskirts of Peterborough. Because of that, it was known as the Pontypool–Peterborough Road. It was eventually extended to Highway 7 on the east side of Peterborough and later widened to a four-lane expressway in the late 1980s. Since then, improvements have been proposed to extend Highway 115 east to Highway 28, but none has come to fruition. In 1953, construction began on a two-lane road northeastward from Highway 35 south of Pontypool, with the purpose of creating a shorter route between Toronto and Peterborough. The Pontypool–Peterborough Road, as it was referred to during construction, was completed and designated as Highway 115 on March 17, 1955, ending at an intersection with
Highway 28 which became notoriously dangerous. Highway 115 was later extended east to connect with the bypass, and the northern terminus became the intersection of Erskine Avenue and Lansdowne Street (the former Highway 7A). The extension was opened at a ribbon-cutting ceremony on August 25, 1978. The entire length of the highway south of Highway 7 was widened to four lanes in the 1980s and early 1990s. Later, Highway 115 was rerouted to join Highway 7 on the newly-four-laned Peterborough By-pass route. Although Highway 115 currently meets many
Ontario freeway design standards northeast of the Highway 35 interchange, there are currently no plans to re-designate this section as a 400-series highway (like Highway 415 or a non-tolled section of Highway 407). == Exit list ==