After forming a part of the Kansas border in NW Missouri, transects the state in a general E~ direction beginning at Kansas City and Independence, MO. It empties into the Mississippi River just north of St Louis, MO.
The 2,315-mile long river is America's 2nd longest with its headwaters in the Rocky Mtns in SW Montana's Yellowstone Country, at Missouri Headwaters State Park. Flowing through Missouri River Country it reaches a width of over 1 mi. and depths to 125 ft. It pours 69,300 cubic feet of water per second into the Mississippi River along with 250,000,000 cubic yards of silt per year.
Major tributaries include the Yellowstone River, Cheyenne, See: Thunder Basin National Grassland, Kansas River, (While not in Kansas, the North Platte River & South Platte River).
Major cities along the Missouri include Sioux City, Omaha, St Joseph & St Louis.
The lower reaches of the river were explored by Louis Joliet and Pere (Father) Jacques Marquette in 1673. Lewis and Clark explored the entire length of the river between 1804 and 1806.