The Cass Expedition was the 1820 exploratory party of Brigadier General Lewis Cass (1782-1866), the governor of Michigan Territory and renowned explorer, Henry Rowe Schoolcraft (1793–1864), served as the expedition’s geologist.
The Cass Expedition was chartered to map the area of Minnesota and to search for the source of the Mississippi River. It was approved by the then U.S. Secretary of War, John C. Calhoun (1782-1850). While the mapping effort was, for the most part, successful, they incorrectly identified the source of the Mississippi. (This error was finally rectified when Schoolcraft conducted his own expedition in 1832.) While returning to Detroit, they were also charged with the mapping of the coast of Lake Michigan, which is why Wolcott was there in the first place.