Fond du Lac was incorporated in 1857 and became a part of the City of Duluth in 1895. It was the site of a major Chippewa Indian settlement from the sixteenth through the nineteenth centuries and stood on an early canoe route along the St. Louis River from Lake Superior to Lake Vermillion and the Upper Mississippi. Daniel Graysolon, Sieur du Lhut, visited the site in 1679. The American Fur Company established a trading post there in 1817. Louis Cass camped there in 1820 while searching for the source of the Mississippi River, as did Henry R. Schoolcraft in 1826. The Chippewa Indian Treaty, negotiated by Cass, was signed at Fond du Lac in 1826. A branch of the Superior-St. Paul Military Road was built to Fond du Lac about 1856, and the first railroad to reach Duluth, the Lake Superior and Mississippi, was constructed through the settlement in 1870.