Ontario Highway 138

Highway 138
Route information
Maintained by the Ministry of Transportation
Length	38.7 km[1] (24.0 mi)
Existed	May 1, 1967[2]–present
Major junctions
South end	9th Street West in Cornwall (formerly Highway 2 east)
Major intersections	Highway 401 in Cornwall
North end	Highway 417 / TCH near Casselman
Location
Country	Canada
Province	Ontario
Counties	Stormont, Dundas and Glengarry United Counties
Towns	Saint Andrews, Monkland
Highway system
Ontario provincial highways Current Former 400-series
← Highway 137 → Highway 140

King's Highway 138, commonly referred to as Highway 138, is a provincially maintained highway in eastern Ontario, Canada. It extends from former Highway 2 in Cornwall, north to Highway 417 east of Casselman. Highway 138 provides access to the Seaway International Bridge, connecting Cornwall with Massena, New York. The highway is 38.7 km (24.0 mi) in length.

Highway 138 was first established in 1967, connecting Highway 2, now Vincent Massey Drive, with Highway 43 in Monkland. By the mid-1970s, the route had been extended north to meet with the newly opened Highway 417. Since then it has remained unchanged.