Dogtooth Island is a landlocked fluvial island adjacent to the Mississippi River.
Approximately 3 miles (4.9 km) long, it is part of Alexander County in the U.S. state of Illinois.
The nearest community is Willard, Illinois.
[1] The patch of wetland, still called by courtesy an "island", is on the tip of Dogtooth Bend, a fluvial oxbow-peninsula formed by a meander of the Mississippi Rivber.
Much of the Island has been placed in conservation easement for purposes of wetland reserve and floodplain restoration.