Horseshoe Lake in Madison County, Illinois, is a 2,400-acre natural oxbow lake formed over 10,000 years ago when the Mississippi River changed course. As Illinois's second-largest natural lake and a designated National Natural Landmark, it offers unique paddling opportunities just minutes from St. Louis in the American Bottom floodplain. The lake is exceptionally shallow, averaging only 3 feet deep throughout most of its expanse, making it ideal for kayaking and canoeing. Paddlers can explore distinctive horseshoe-shaped waters that wind through diverse habitats including cypress-tupelo swamps that evoke a bayou atmosphere. The shallow, calm conditions are perfect for beginners and families, though the extensive surface area provides ample room for experienced paddlers to explore.

Access is available at Horseshoe Lake State Park, which encompasses 2,960 acres surrounding the lake. The park provides boat launch facilities, with the main access points located off Highway 111 near Granite City. Multiple launch areas allow paddlers to explore different sections of the lake.

Wildlife viewing is exceptional here, with 287 documented bird species making this a premier birding destination. Paddlers regularly encounter great blue herons, great egrets, wood ducks, and various migratory waterfowl. Canada geese winter in large numbers, and bald eagles can be spotted during colder months. The Eurasian tree sparrow, found nowhere else in North America outside this region, inhabits the area.

The lake's most striking feature is the 200-acre tree kill on the eastern shore, where carbon dioxide seeping from the ground has created a haunting landscape of standing snags—a dramatic natural phenomenon visible from the water. The western shoreline is industrialized with the U.S. Steel Granite City Works facility, while other areas retain a wild, natural character. Paddlers should note that the park annually drains portions of the lake to provide shorebird habitat, so water levels can vary seasonally. The lake supports fishing for bass, crappie, bluegill, and catfish, and no swimming or jet skiing is permitted, preserving quiet conditions for paddling.