Great Marsh comprises hundreds of lots in the Town of Beverly Shores. Most of the protected land falls within the Great Marsh, the vast wetland that once paralleled the shoreline of Lake Michigan from Gary to Michigan City. A healthy marsh ecosystem is being restored here on land that was drained for development in the early 20th century.
A superb spot for birding enthusiasts, it is a designated stop on the Chicago Region Birding Trail and has been recognized as an Important Bird Area by the National Audubon Society. A variety of waterfowl and wading birds are common, and sandhill cranes have recently begun nesting here.
The area also contains two small rare-plant refuges, McAllister Prairie and Hiawatha Meadow. Two short trails are located here, and visitors can view much of the area from Beverly Drive.