↑ The United States Geological Survey recognizes two contrasting definitions of a river's source. By the stricter definition, the Mississippi would share its source with its longest tributary, the Missouri, at Brower's Spring in Montana. The other definition acknowledges "somewhat arbitrary decisions" and places the Mississippi's source at Lake Itasca, which is publicly accepted as the source, and which had been identified as such by Brower himself.
↑ Median of the 1,826 daily mean streamflows recorded by the USGS for the period 1978–1983 at Baton Rouge.
