Sarnia is a city in Southwestern Ontario located on the eastern bank of the junction between the Upper and Lower Great Lakes where Lake Huron flows into the St. Clair River, which forms the Canada-United States border, directly across from Port Huron, Michigan. It is the largest city on Lake Huron. The name "Sarnia" is Latin for Guernsey, which is a British Channel Island.The city's natural harbor first attracted the French explorer LaSalle, who named the site "The Rapids" when he had horses and men pull his forty-five-ton barque "Le Griffon" up the almost four-knot current of the St. Clair River in August 1679. This was the first time anything other than a canoe or other oar-powered vessel had sailed into Lake Huron.The Sarnia port remains an important center for lake freighters and oceangoing ships carrying cargoes of grain and petroleum products. The natural port and the salt caverns that exist in the surrounding areas, together with the oil discovered in nearby Oil Springs in 1858 led to the massive growth of the petroleum industry in this area. Because Oil Springs was the first place in Canada and North America to drill commercially for oil, the knowledge that was acquired there led to oil drillers from Sarnia traveling the world teaching other nations how to drill for oil.