Route 138 is a major highway in the Canadian province of Quebec, following the entire north shore of the Saint Lawrence River past Montreal to the temporary eastern terminus in Kegashka on the Gulf of Saint Lawrence. The western terminus is in Elgin, at the border with New York State south-west of Montreal. Part of this highway is known as the Chemin du Roy, or King's Highway, which is one of the oldest highways in Canada.

Tadoussac is a village municipality in La Haute-Côte-Nord RCM, on the north shore of the maritime section of the estuary of St. Lawrence river, in Côte-Nord region, Quebec, Canada.