Area codes 418, 581, and 367 are telephone area codes in the North American Numbering Plan (NANP) for the eastern portion of the Canadian province of Quebec. Area code 418 was originally assigned to the numbering plan area, but all three area codes now form an overlay plan for this territory. Cities in the numbering plan area include Quebec City, Saguenay, Lévis, Rimouski, Saint-Georges, Alma, Thetford Mines, Sept-Îles, Baie-Comeau and Rivière-du-Loup. Also served are the Gaspé Peninsula, Côte-Nord, southeastern Mauricie, and the tiny hamlet of Estcourt Station, in the U.S. state of Maine.

Saguenay is a city in the Saguenay–Lac-Saint-Jean region of Quebec, Canada, on the Saguenay River, about 200 kilometres (120 mi) north of Quebec City by overland route. It is about 126 kilometres (78 mi) upriver and northwest of Tadoussac, located at the confluence with the St. Lawrence River. It was formed in 2002 by merging the cities of Chicoutimi and Jonquière and the town of La Baie. Chicoutimi was founded by French colonists in 1676. As of July 2021, the city had a population of 145,000 and the metropolitan area had a population of 165,000.