The Middle Mississippi River National Wildlife Refuge was established as a refuge on May 31, 2000. The refuge is currently 8,074 acres on both the Illinois and Missouri side of the Mississippi River. Middle Miss., as the locals refer to it, contains seven divisions including the Meissner Island Division near Valmeyer, Illinois; Harlow Island Division near Festus, Missouri; Beaver Island and Horse Island Divisions near Kaskaskia, Illinois; Crains Island Division across the river from Chester, Illinois; Rockwood Island Division near Rockwood, Illinois; and the Wilkinson Island Division near Gorham, Illinois.
Middle Mississippi River National Wildlife Refuge lands were purchased in response to the great flood of 1993 and are unique in the refuge complex. The refuge tracts lie within the uncontrolled portion of the Middle Mississippi River, below the confluence with the Missouri, where river levels are not regulated by the lock and dam system. Water levels may fluctuate greatly in this "open river" section of the Mississippi, and frequent flooding occurs on these lands.
Much of the refuge land had previously been cut off from the floodplain by private levees that protected agricultural lands. Most of the levees were breached by the 1993 flood and will not be repaired. These lands will provide access to the floodplain for native fish during high water stages and create a corridor of floodplain forest habitat for migratory birds and resident wildlife. The refuge was designated as an Important Bird Area in 2008.
Frequent flooding occurs on refuge tracts due to their position in the river floodplain. Modifications to man-made structures such as levees promotes healthy and diverse fish habitat for native Mississippi River fishes. Where possible, old river channels and swales are managed with passive water control structures to provide seasonal wetlands for migratory birds. By allowing these lands to flood and re-connect with the river, the refuge contributes to the overall health of the ecosystem. Former agricultural lands are allowed to return to forested habitat, with the occasional tree plantings to promote species diversity and abundant food for native wildlife. Many species of fish and wildlife will benefit from the habitat restoration, and the public will have increased opportunities for wildlife-dependent outdoor recreation.