Arkansas River GeographyThe Arkansas River headwaters source is near Leadville,Guest Posting Colorado. The river technically ends in the Mississippi, which leads out to the ocean. The river drops 10,000 feet in the first 125 mile stretch. Within this stretch, the River carves through a large canyon now called the Royal Gorge. Because of the rapid drop of elevation, this stretch of river is popular for whitewater rafting and other river recreation. In total, the river drops 11,400 feet and covers a total of 161,000 square miles. The Arkansas River basin drains 24,904 square miles.From Colorado, the Arkansas River then runs through Kansas, Oklahoma and Arkansas, before meeting up with the Mississippi River. In total the river runs 1450 miles, which makes the Arkansas River the longest tributary in the Mississippi-Missouri water system.Carving out many canyons and gorges, perhaps one of the most well known is the Royal Gorge. With a width of 50 feet at its base and a few hundred feet at its top, and a depth of 1200 feet in places, the 10-mile-long canyon is a narrow, steep crevasse through the granite of Fremont Peak.The Arkansas River is now used as a main waterway for commerce, with the system being formerly called the McClellan-Kerr Arkansas River Navigation System or MKARNS. This specific stretch of the river is 445 miles. It takes a commercial towboat 5 days to travel the MKARNs distance. The commercial stretch of the river has multiple dam and lock systems allowing for greater control over the navigation efforts. The Arkansas River is used for waterway commerce, recreational activities (such as whitewater rafting) and wildlife preservation.Arkansas River HistoryThe Arkansas River was first discovered by Europeans before the Mississippi River in 1541. After Francisco Vasquez de Coronado forded the river, Hernando de Soto was on the lower river, when he later discovered the Mississippi.