The Gensburg-Markham Prairie, also known as Markham Prairie, is a 105.6-acre (427,000 m2) high-quality tallgrass prairie located in Markham in the Chicago metropolitan area. It is part of the larger Indian Boundary Prairies managed by Northeastern Illinois University and The Nature Conservancy. Described by the Illinois Department of Natural Resources as "an unusual example of sandy loam prairie," it is a National Natural Landmark.