Note:  Do not rely on this information. It is very old.

Missouri

Missouri ("Great Muddy"). The real headstream of the Mississippi; it is formed by the junction of the Jefferson, Madison, and Gallatin, yvhich flow N. from the Wind River Mountains, on the borders of Wyoming and Idaho, and unite at Gallatin city, Montana, in lat. 45 54' N., long. 111 30'W. Its course thence is N. as far as Fort Benton (about 200 miles), whence it trends towards the E. About 90 miles beyond Gallatin city it passes through the "Gate of the Mountains," a magnificent gorge nearly six miles long, with precipitous cliffs of granite (1,200 feet in height) on either side. At the Great Falls, 60 miles below the Gate, the river descends 327 feet in 15 miles, the highest single fall being 87 feet. From Fort Benton it flows E. through Montana and part of Dakota, then S. and S.E. through Dakota and between Iowa and Missouri on the left, and Nebraska and Kansas on the right, as far as Kansas city, where it turns E., joining the Mississippi 20 miles above St. Louis. Its chief tributaries are the Yellowstone, Platte or Nebraska, and Kansas, all on the right bank. The river can be ascended to Fort Benton, or, in the dry season, to the Yellowstone; but navigation is dangerous, and has to be almost completely abandoned in favour of railway communication. The waters of the Missouri are turbid, and it has a swift current. The total length is 3,047 miles.