The 160-square-mile Calumet region is a study in contrasts. Running along the southwest shore of Lake Michigan, the Calumet region includes a significant portion of the City of Chicago and sweeps east, encompassing Gary, Indiana, and the Indiana Dunes National Lakeshore. Once one of the largest wetland complexes in North America, the Calumet region later became the heart of the US steel industry. Heavy industrial development dramatically altered Calumet's landscape and ecosystems. Slag, a byproduct of steel-making, was disposed of along Lake Michigan and in many of the wetlands. Rivers were dredged and channelized, wetlands were filled, and natural habitat disrupted. Still, and surprisingly, rare bird species flourish in the Calumet region in remnant natural areas. Many of the industries that transformed the Calumet region have disappeared, and with them, countless jobs. Numerous industrial sites have now been abandoned, dotting the landscape with properties that are contaminated or are perceived to be contaminated, known as brownfields. Although the region is a classic example of the rust belt, many industries still thrive there. In the meantime, remaining natural areas in the Calumet continue to draw recreationists who hope to see rare birds.
Lake Calumet hosts breeding and foraging sites for a variety of waders. A breeding colony of Black-crowned Night-Herons has existed in the Calumet region for years, with 300 breeding pairs observed at the site in the year 2003. Also breeding that year were five pairs of Common Gallinule. The area has one of the largest Willow Flycatcher populations in the state. Another regular breeder, though in low numbers, is the Least Bittern. Large numbers of gulls winter here, and the site contains one of the Chicago region's largest colonies of nesting Herring and Ring-billed Gulls. This site was chosen as an IBA because it met the criteria for breeding Black-crowned Night-heron, Common Gallinule, and Willow Flycatcher.
The Lake Calumet area is under the ownership of various players. The major owners are: Eggers Woods, Powderhorn Lake, Beaubien Woods (County), Wolf Lake (State), Lake Calumet (Port Authority), Deadstick Pond (Metropololitan Water Reclamation District), Indian Ridge Marsh, Hegewisch Marsh, Heron Pond, Van Vlissengen Prairie, and Big Marsh (City of Chicago).
Small acreages of marshland, woods, prairie and lake exist among a large industrial corridor at Lake Calumet.