Lake Michigan, the sixth largest lake in the world, was discovered in 1634 by Jean Nicolet, who explored this north shore to Green Bay but found no Orientals as the French in Quebec had hoped he would. In the 1670’s, Marquette and Jolliet established the lake’s general size and outline and named it Lake Michigan. Its elongated shape was an obstacle to transcontinental expansion, but its waters soon proved a real boon to commerce.