The Arkansas River (Pawnee: Kícka ) is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast as it traverses the US states of Colorado, Kansas, Oklahoma, and Arkansas. The river's source basin lies in the western United States in Colorado, specifically the Arkansas River Valley, where the headwaters derive from the snowpack in the Sawatch and Mosquito mountain ranges. Then it flows east into the Midwest via Kansas, and finally into the South through Oklahoma and Arkansas.