The New International Encyclopædia/Arkansas River
ARKANSAS RIV′ER. Next to the Missouri, the largest affluent of the Mississippi River (Map: United States, Eastern Part, G 3). It rises in Central Colorado, flows east into Kansas, and out again east of the middle of the south boundary of the same State, southeast across Oklahoma and Indian Territories, and diagonally across Arkansas, bisecting it into nearly equal parts, and emptying into the Mississippi. The river is about 2000 miles long, navigable for 650 miles, and drains an area of 188,000 square miles. Much of the water in its upper course is used for irrigation purposes. In Fremont County, in Central Colorado, it flows through the Royal Gorge, one of the deepest cañons in the United States. In its upper course the current is very rapid, but in its lower portion the bed is sandy and broad. It receives the Salt Fork and Cimarron from the west in Oklahoma, and in the Indian Territory the Canadian from the west and the Verdigris and Grand rivers from the north.