Ontario Highway 138 History - The King's Highways of Ontario

King's Highway 138 is an arterial highway in Eastern Ontario, which has served the Counties of Stormont, Dundas and Glengarry since the late 1960s. The highway's primary function is to connect the City of Cornwall with Highway 417 east of Ottawa. In 1966, the Department of Highways of Ontario (DHO) completed a major transportation study in Eastern Ontario. Among the study's many recommendations was the establishment of a new provincial highway link from Cornwall to the proposed route of Highway 417 near Casselman. The highway was acquired by the DHO in two stages between 1967 and 1971. A Preliminary Assumption Plan was prepared dated February 16, 1967, which showed the proposed assumption of Stormont County Road 16 from the Cornwall City Limits northerly to Highway 43 at Monkland as a new King's Highway. The plan was registered on April 3, 1967 and the route was designated as King's Highway 138 by an Order-in-Council, effective April 27, 1967. Once construction got underway on Highway 417 east of Ottawa in the 1970s, Highway 138 was extended north along the remaining portion of Stormont County Road 16 from Monkland to meet the new route of Highway 417 east of Casselman. The extension of Highway 138 from Highway 43 to Highway 417 was shown on a Preliminary Assumption Plan dated July 15, 1971. The plan was registered on July 30, 1971 and was designated by an Order-in-Council, effective October 10, 1971.

As originally established in 1967, provincial jurisdiction of Highway 138 ended at the Cornwall City Limits at Cornwall Centre Road. The portion of Highway 138 lying within the City of Cornwall was owned entirely by the municipality and was thus not maintained by the Ministry of Transportation. However, a Municipal Connecting Link was established in 1971 which extended along Cornwall Centre Road and Brookdale Avenue in order to connect the otherwise discontinuous route of Highway 138 to Highway 401. The route of Highway 138 has remained unchanged since the 1970s. A 3 1/2-mile diversion of Highway 138 was designated in 1969, but was never constructed. This diversion was essentially a northerly extension of Brookdale Avenue from the turn at Cornwall Centre Road northerly to a point just north of St. Andrews. The Municipal Connecting Link route through Cornwall that followed Cornwall Centre Road and Brookdale Avenue from the northern city limits southerly to the Seaway International Bridge Approach is only signed as Highway 138 as far south as the Highway 401 Interchange today.

Highway 138 is a two-lane highway for its entire length. The highway passes through predominantly rural areas along its 36 km route. Services are rather scarce along this highway outside of larger communities. The speed limit on Highway 138 is 80 km/h (50 mph), unless posted otherwise. Please visit the Highway 138 Mileage Chart page for a list of mileage reference points along Highway 138.