Mississippiriver

Mississippi (river). A river of North America, 2,960 miles in length, or, if the Missouri rather than the Upper Mississippi be regarded as the head-stream, 4,200 miles. With the exception of about 12,000 square miles drained by the Milk river and situated in British America, its basin of 1,257,545 square miles lies wholly within the United States. It rises in the state of Minnesota in lat. 47° 6' N., long. 95° 15' W., where several small streams unite to form Lake Itasca. It flows generally south, with a slight inclination towards the east; but in some parts its course is so involved that it almost returns upon itself. Its chief tributaries besides the Missouri (q.v.) are the St. Croix, Chippeway. Wisconsin, Illinois, and Ohio on the east, and the Minnesota, Iowa, Des Moines, Arkansas, and Red River on the west. At first it passes, with numerous falls and rapids, through a wild and almost unexplored region of prairie, swamp, and pine-forest. In Wisconsin begin the bluffs which henceforward frequently line its course, and below the influx of the Ohio sometimes rise abruptly to a height of 250 feet on the east bank; on the west bank they are less precipitous, and situated at a greater distance from the river, owing to the alluvial deposits brought down by the tributaries on this side, which form a plain varying from 30 to 150 miles in width. Below the Red River the stream divides into numerous channels, which find their way to the Gulf of Mexico through a marshy and perfectly level district with but few inhabitants.

New Orleans is situated near the mouth. The main channel is entered through several mouths at the end of a long tongue of land in long. 89° W. The floods produced by the spring rains and the melting of the snow in the upper basin extend from February to June. The surrounding country is now protected by embankments called "levees;" but between the Ohio and the Red River they are broken through at intervals of about ten years, when the water sometimes rises 50 feet, and the river frequently shifts its course permanently for some distance. In some places the surface, but not the bed of the river, is higher than that of the land in the neighbourhood. The Mississippi is navigable as far as Minneapolis, 2,160 miles above its mouth. The chief dangers of navigation, in addition to those caused by the falls and rapids (now averted by the construction of ship canals) are the "snags" and "sawyers," or trees carried down by the floods, and the vast deposits near the mouth which are constantly shifting their position; but a fixed channel, over 30 feet deep, is now secured through the jetties designed by Captain J. B. Eads.