Horseshoe Lake is an oxbow lake

Oxbow lake

An oxbow lake is a U-shaped body of water formed when a wide meander from the main stem of a river is cut off to create a lake. This landform is called an oxbow lake for the distinctive curved shape, named after part of a yoke for oxen. In Australia, an oxbow lake is called a billabong, derived...

 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...

, Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

. It is the site of Illinois's Horseshoe Lake State Fish and Wildlife Area

Horseshoe Lake State Fish and Wildlife Area

Horseshoe Lake State Fish and Wildlife Area is an Illinois state park on in Alexander County, Illinois, United States. Also see: Horseshoe Lake...

, a state park 10645 acres (43 km²) in size. A remnant of a large meander of the Mississippi River, it is today a shallow, isolated patch of water located near Cairo

Cairo, Illinois

Cairo is the southernmost city in the U.S. state of Illinois. It is the county seat of Alexander County. Cairo is located at the confluence of the Mississippi and Ohio rivers. The rivers converge at Fort Defiance State Park, an American Civil War fort that was commanded by General Ulysses S. Grant...

 and the southern tip of Illinois.

The Alexander County lake has major problems with siltation. During the Great Flood of 1993

Great Flood of 1993

The Great Mississippi and Missouri Rivers Flood of 1993 occurred in the American Midwest, along the Mississippi and Missouri rivers and their tributaries, from April to October 1993. The flood was among the most costly and devastating to ever occur in the United States, with $15 billion in damages...

 the river tried to shift back to the Horseshoe Lake meander, but returned to its modern channel after the flood subsided. Much of the lake resembles a swamp or bayou. This is the northernmost part of the natural range of the Bald cypress and Tupelo

Tupelo

The tupelo , black gum, or pepperidge tree, genus Nyssa , is a small genus of about 9 to 11 species of trees with alternate, simple leaves...

 trees, which are found on the shoreline of the lake. Another tree found here is the swamp cottonwood

Populus heterophylla

Populus heterophylla, known as the Swamp Cottonwood, also called the River Cottonwood, Downy Poplar, Swamp Poplar, or Black Cottonwood which is actually Populus trichocarpa, is a large deciduous Poplar belonging to section Leucoides of the larger Salindaceae family, found in wet bottom land...

. There is a good growth of the flowering American lotus

Nelumbo lutea

Nelumbo lutea is a species of flowering plant in the monogeneric family Nelumbonaceae. Common names include American lotus, yellow lotus, water-chinquapin, and volée. It is native to North America...

.