I.

Introduction

Mississippi (river) (Algonquian Misi sipi, “big river”), river, central United States, one of the longest rivers of North America. The Mississippi River system is mainly within the United States, with the headwaters of the Missouri River, the main Mississippi tributary, extending into Canada. The Mississippi is exceeded in length by the Missouri and Mackenzie rivers, but it discharges a greater volume of water than any other river on the North American continent. It drains most of the country’s central plains between the Rocky and Appalachian mountains, an area of about 3,256,000 sq km (1,257,000 sq mi).

In addition to the Missouri, the Mississippi is fed by the Red, Arkansas, and Ohio rivers and by about 250 other tributaries. The total length of the Mississippi is 3,779 km (2,348 mi), and the total navigable length of all the rivers in the system is about 25,900 km (16,100 mi). The Mississippi-Missouri-Red Rock river system is approximately 5,970 km (3,710 mi) long, making it the fourth longest river system in the world.