> The Missouri is the largest tributary of the Mississippi River, which flows into the Gulf of Mexico He must mean longest. This chart[0] shows that the Ohio

> The Missouri is the largest tributary of the Mississippi River, which flows into the Gulf of Mexico He must mean longest. This chart[0] shows that the Ohio is by far the largest tributary of the Mississippi by volumetric flow, and also shows the Atchafalaya bifurcation. However, the wiki articles for the Missouri[1] and Ohio[2] show average discharges into the Mississippi of 87,520 cu ft/s and 281,000 cu ft/s, respectively. Not as great a difference as the first chart [0] shows, but still significantly different. Even more interesting, since the Missouri drainage basin is about 2.5x larger. [0]https://en.wikipedia.org/wiki/Mississippi_River#/media/File:Mississippi_River_flow.gif https://en.wikipedia.org/wiki/Mississippi_River#/media/File:... [1]https://en.wikipedia.org/wiki/Missouri_River https://en.wikipedia.org/wiki/Missouri_River [2]https://en.wikipedia.org/wiki/Ohio_River https://en.wikipedia.org/wiki/Ohio_River