Clear Creek is a southern Illinois watercourse that rises in Jackson County

Jackson County, Illinois

Jackson County, incorporated January 10, 1816, is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 60,218, which is an increase of 1.0% from 59,612 in 2000...

 and Union County, and discharges into the Mississippi River

Mississippi River

The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

 in Alexander County

Alexander County, Illinois

Alexander County is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 8,238, which is a decrease of 14.1% from 9,590 in 2000. Its county seat is Cairo. Alexander County is part of the Cape Girardeau–Jackson, MO-IL Metropolitan Statistical...

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Upper and lower halves

Clear Creek is neatly divided by the bluffs of the Mississippi into two sections: nearer its headwaters it is a relatively clean and swift-flowing hill river, and in its lower half, below the bluff, it has become a channelized ditch, the Clear Creek Ditch.

Clear Creek rises in the uplands of the Shawnee Hills

Shawnee Hills

The Shawnee Hills is a region of Southern Illinois that rests mainly in an east-west arc roughly following the outline of the southern end of the Illinois Basin. Whereas Mississippian and Pennsylvania Age rock layers are deep beneath the surface in central Illinois, these strata pierce the surface...

 near Cobden, Illinois

Cobden, Illinois

Cobden is a village in Union County, Illinois, United States. The population was 1,157 at the 2010 census. It is named after British politician and free-trade advocate Richard Cobden, who visited the town in 1859. Cobden originated as a farming community known for its apples and peaches...

. In its upper reaches, Clear Creek is an unusually clean and undisturbed stream for Illinois, as its watershed includes two of the largest wilderness

National Wilderness Preservation System

The National Wilderness Preservation System of the United States protects federally managed land areas designated for preservation in their natural condition. It was established by the Wilderness Act upon the signature of President Lyndon B. Johnson on September 3, 1964...

 areas in Illinois, Bald Knob Wilderness

Bald Knob Wilderness

The Bald Knob Wilderness is a 5,973-acre parcel of land listed as a Wilderness Area of the United States. It is, by acreage, the largest wilderness area located within the U.S. state of Illinois...

 and Clear Springs Wilderness

Clear Springs Wilderness

The Clear Springs Wilderness is a 4,730-acre parcel of land listed as a Wilderness Area of the United States. It contains the LaRue-Pine Hills Ecological Area, a National Natural Landmark noted for a large and diverse population of snakes....

. Another section of the creek's watershed is protected by the Trail of Tears State Forest

Trail of Tears State Forest

Trail of Tears State Forest is a State of Illinois conservation area on in Union County, Illinois, United States.Trail of Tears was established in 1929 when Illinois purchased acres of Shawnee Hills land and used the resulting land to create the Kohn-Jackson Forest...

, and most of the remainder of the watershed is protected by the non-wilderness parcels of Shawnee National Forest

Shawnee National Forest

The Shawnee National Forest, located in the Ozark and Shawnee Hills of Southern Illinois, consists of approximately 280,000 acres of federally managed lands. In descending order of land area it is located in parts of Pope, Jackson, Union, Hardin, Alexander, Saline, Gallatin, Johnson, and Massac...

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West of Jonesboro, Illinois

Jonesboro, Illinois

Jonesboro is a city in Union County, Illinois, United States. The population was 1,853 at the 2000 census. It is the county seat of Union County, and was the location of the third of the Lincoln-Douglas debates, on 15 September 1858.-Geography:...

, Clear Creek descends from the Shawnee Hills into the bottomland of the Mississippi River. In historical times, the stream fed a ribbon-shaped wetland

Wetland

A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

 that ran southward and parallel to the Mississippi River for approximately 15 miles (24 km) before discharging into a former watercourse of the main river, the Picayune Chute, east of Cape Girardeau, Missouri

Cape Girardeau, Missouri

Cape Girardeau is a city located in Cape Girardeau and Scott counties in Southeast Missouri in the United States. It is located approximately southeast of St. Louis and north of Memphis. As of the 2010 census, the city's population was 37,941. A college town, it is the home of Southeast Missouri...

. Part of this wetland has been conserved as the Union County State Fish and Wildlife Area

Union County State Fish and Wildlife Area

Union County State Fish and Wildlife Area is an Illinois state park on in Union County, Illinois, United States. It contains extensive Clear Creek wetlands managed for fishing and bird hunting....

, but during the 20th century most of it was extensively ditched and drained for mosquito

Mosquito

Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...

 abatement and to promote agriculture

Agriculture

Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

. Engineers dug a ditch that carries Clear Creek's drainage southward a further eight miles (13 km) and takes in further runoff from adjacent Shawnee Hills creeks. The creek/ditch currently discharges into the Mississippi close to Thebes, Illinois

Thebes, Illinois

Thebes is a village in Alexander County, Illinois, United States. The population was 478 at the 2000 census. It is part of the Cape Girardeau–Jackson, MO-IL Metropolitan Statistical Area.-Geography:Thebes is located at ....

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