Marshall State Fish and Wildlife Area, located in the northwest region of the state along nearly 10 miles of scenic Illinois River backwaters, bottomlands and bluffs, lies in the heart of the Mississippi flyway and supports a wide variety of wildlife.
With an initial land purchase by the State of Illinois in 1925, the area has grown to include approximately 6,000 acres, of which half is land and half is water divided into three units. The largest of these is the Marshall Unit, consisting of 3,000 acres east of the Illinois River and adjacent to Route 26. The Spring Beach Unit contains 1,642 acres (537 acres of water) on the west side of the Illinois River between Sparland and Chillicothe. The unit falls in both Marshall and Peoria counties. The Sparland Unit, the smallest of the three, consists of 1,280 acres, of which 1,110 acres are water. It is located between Route 29 and the Illinois River. On the east side of Route 26 and the west side of Route 29 are high bluffs containing heavy hardwood timber of oaks, hickories and walnuts interspersed with wildflowers and shrubs.
The backwater lakes at this state wildlife area attract large flights of waterfowl during migration. The Wood Duck also breeds here.
Great Egrets and Great Blue Herons can be found foraging in the backwaters during breeding and migration. Double-crested Cormorant also breeds here.
In winter, Bald Eagles search for fish in open waters and roost at night. Diving ducks also spend winter here if there is sufficient open water.
This site was chosen as an IBA because it meets the criteria for migrating waterfowl.
This state wildlife area continas high bluffs, which slope to bottomland hardwood forests and backwater lakes. Upland soils are thick loams. Bottomland soils are primarily alluvial sediments with some thin loamy or silty materials on gravelly, Wisconsinan outwash.
Plant communities are representative of glacial drift hill prairie, dry-mesic upland forest (white oak and hickory), and wet bottomland forest (cottonwood, silver maple, and willow).