Sarnia is a city in Southern (Southwestern) Ontario, Canada (city population 71,419, census area population 88,793, in 2006). The city is considered part of the Detroit-Windsor metropolitan area. It is the largest city on Lake Huron and is located where the upper Great Lakes empty into the St. Clair River. The city's natural harbour first attracted the French explorer La Salle, who named the site "The Rapids". The name "Sarnia" was the Latin name for Guernsey in the Channel Islands just off the coast of Normandy, France. The Sarnia port is still an important centre for lake freighters and "salties" carrying cargoes of grain and petroleum products. It is the largest community in Lambton County.