Port-Cartier is a city in the Côte-Nord region of Quebec, Canada. It is located on the north shore of the St. Lawrence River at the mouth of t…Port-Cartier is a city in the Côte-Nord region of Quebec, Canada. It is located on the north shore of the St. Lawrence River at the mouth of the Aux-Rochers River, 63 kilometres southwest of Sept-Îles, Quebec.