The Kuskokwim River or Kusko River (Yup'ik: Kusquqvak; Deg Xinag: Digenegh; Upper Kuskokwim: Dichinanek' ; (Kuskokvim)) is a river, long, in Southwest Alaska in the United States. It is the ninth largest river in the United States by average discharge volume at its mouth and seventeenth largest by basin drainage area. The Kuskokwim River is the longest river system contained entirely within a single U.S. state. The river provides the principal drainage for an area of the remote Alaska Interior on the north and west side of the Alaska Range, flowing southwest into Kuskokwim Bay on the Bering Sea. The highest point in its watershed is Mount Russell. Except for its headwaters in the mountains, the river is broad and flat for its entire course, making it a useful transportation route for many types of watercraft, as well as road vehicles during the winter when it is frozen over. It is the longest free flowing river in the United States. Kuskokwim is a loose transliteration of a Yup'ik word. It is a compound word meaning big slow moving thing. The Alaska Natives of Kuskokwim are Yup'ik Eskimo on the lower Kuskokwim, Deg Hit'an Athabaskan on the middle Kuskokwim, Upper Kuskokwim Athabaskan on the upper Kuskokwim, and Koyukon Athabaskan on the North Fork, Lake Minchumina. Name The river's name comes from the Yup'ik, kusquqviim, recorded by a Russian sailor in 1826. The Tanana (Athabaskan) name for the river was Chin-ana. Upper Kuskokwim (Kolchan) is often used to mean the people of the upper parts of the river, while Yup'ik people live along the lower river. Course The river is formed by the confluence of East Fork Kuskokwim River and North Fork Kuskokwim River, east of Medfra. From there it flows southwest to Kuskokwim Bay and the Bering Sea. The Kuskokwim is fed by several forks in central and south-central Alaska. The North Fork (250 mi/400 km) rises in the Kuskokwim Mountains approximately 200 miles (320 km) WSW of Fairbanks and flows southwest in a broad valley. The South Fork (200 mi/320 km) rises in the southwestern end of the Alaska Range west of Mount Gerdine and flows north-northwest through the mountains, past Nikolai, receiving other streams that descend from the Alaska Range northwest of Denali. The two forks join near Medfra, and from there the main stem of the Kuskokwim flows southwest, past McGrath, in a remote valley between the Kuskokwim