How long is the river that bounds the Mid-Continent Region on the west?
Mid-Continent Region (North America):  It is bounded by the Mississippi River on the east and the Missouri River on the west and consists of generally low-relief, flat-lying marine and stream deposits from the Mesozoic and Cenozoic Eras. Missouri River:  Rising in the Rocky Mountains of western Montana, the Missouri flows east and south for 2341 mi before entering the Mississippi River north of St. Louis, Missouri.
i don't know