North Dakota Highway 1806 (ND 1806) is a state highway in the U.S. state of North Dakota. ND 1806 and ND 1804 were named to reflect the years of Lewis and Clark's travels through the area, and run along the southwest and northeast sides of the Missouri River, respectively. ND 1806 consists of four separate segments, running along Lake Sakakawea and the Missouri River in McKenzie, Dunn, Mercer, Oliver, Morton, and Sioux Counties.