Kaskaskia River

Kaskaskia River
A coal loading facility on the Kaskaskia River near New Athens in St. Clair County, Illinois
Kaskaskia River watershed map
Location
CountryUnited States
Physical characteristics
Source 
  locationInterstate 74 in Champaign County, Illinois west of Champaign, Illinois
  coordinates39°59′30″N 88°21′22″W / 39.991698°N 88.3561656°W / 39.991698; -88.3561656 (Kaskaskia River origin)
  elevation~840 ft (260 m), (Yankee Ridge)
Mouth 
  location
Mississippi River 10 mi (16 km) northwest of Chester
  coordinates
37°58′30″N 89°56′15″W / 37.974942°N 89.937372°W / 37.974942; -89.937372 (Kaskaskia River mouth)
  elevation
~350 ft (110 m)
Lengthapproximately 325 miles (523 km)
Basin sizeapproximately 5,746 sq mi (14,880 km2)
Discharge 
  average14,832 cu ft/s (420.0 m3/s)
Basin features
GNIS ID426395

The Kaskaskia River is a tributary of the Mississippi River, approximately 325 miles (523 km) long, in central and southern Illinois in the United States. The second largest river system within Illinois, it drains a rural area of farms, as well as rolling hills along river bottoms of hardwood forests in its lower reaches. The lower reaches of the river have been canalized to allow barge traffic. In 1819, Vandalia, up the river in the interior of the then new state of Illinois was chosen as its capital, which it served as until 1839.

"Cascasquia" is an alternative, supposedly more French, spelling of "Kaskaskia" that is sometimes encountered. It was named after a clan of the Illiniwek encountered by the early French Jesuits and other settlers. "Okaw River" was an alternative name for the Kaskaskia that persists in place names along the river, including Okawville, and in a major tributary, the West Okaw River.