The Midewin National Tallgrass Prairie in Will County stretches across 20,000 acres—a restoration undertaking of unprecedented scale in the region. This land once hosted the Joliet Army Arsenal, the world's largest ammunition plant. Today, it is the largest protected open space in the Chicago metropolitan area and TWI’s longest-running prairie and wetland restoration effort through an award-winning partnership with the U.S. Forest Service.

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Location and Visiting

Located 60 miles south of downtown Chicago, Midewin National Tallgrass Prairie offers critically important recreational opportunities for the metropolitan region. Midewin is managed by the U.S. Forest Service and open to the public for hiking, tours, bird-watching, horseback-riding, and more. Here visitors can experience a vast example of the Prairie State’s natural heritage, complete with a herd of wild bison. 

Read more: Location and Visiting



The first European settlers in this region were awestruck by the vast, vibrant prairies of Illinois. However, since the 1800’s, the land that is now Midewin National Tallgrass Prairie has undergone extensive alterations, from conversion to agriculture to its use as the world’s largest ammunition plant during World War II. Established in 1996, Midewin is reclaiming its original prairie heritage through an ongoing, large-scale restoration effort. 

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Species List

With less than 0.01 percent of the Prairie State's original prairie ecosystems remaining, Midewin provides critical habitat for many of Illinois' rarest plant, bird, and wildlife species. Below are lists compiled by the U.S. Forest Service of the unique flora and fauna that can be found at Midewin. 

Read more: Species List