Midewin National Tallgrass Prairie: A Visitor's Guide

Twenty thousand acres of open prairie, a free-roaming bison herd, and 33 miles of trails -- all less than an hour from downtown Chicago. Midewin is one of those places you don't fully appreciate until you're standing in it.

From Ammunition Plant to Prairie

The land that became Midewin National Tallgrass Prairie wasn't always grassland. For decades, it served as the Joliet Army Ammunition Plant, producing TNT and other munitions from World War II through the 1970s. Remnants of that era -- bunkers, rail lines, storage magazines -- still dot parts of the landscape.

When the military decommissioned the facility, a coalition of conservationists, local officials, and federal agencies saw an opportunity. Congress authorized the transfer in 1996, making Midewin the first national tallgrass prairie in the country. The US Forest Service took charge, and restoration work began in earnest.

That restoration is ongoing. Crews have been removing old infrastructure, replanting native grass and wildflower species, and gradually returning the land to something resembling pre-settlement Illinois. It's a slow process -- prairie ecosystems took thousands of years to develop -- but the progress over three decades has been striking. What was once concrete and fencing is now home to big bluestem grass, coneflowers, and bison.

The Numbers Worth Knowing

Midewin covers roughly 20,000 acres, making it the largest contiguous open space in the Chicago metropolitan area. That's bigger than Manhattan. About 9,000 of those acres are currently open to public access, with more opening as remediation of former military sites continues.

The trail system spans 33 miles across various loops and connectors. Most paths are flat -- this is Will County, after all -- so the terrain won't challenge experienced hikers. What it lacks in elevation, though, it makes up for in sheer expanse. You can walk for miles without seeing a building or hearing traffic. That kind of quiet is rare this close to a major city.

The Bison Herd

For most visitors, the bison are the main draw. The US Forest Service reintroduced a small herd to Midewin in October 2015, starting with 27 animals from various conservation herds around the country. Bison hadn't roamed this part of Illinois in nearly 200 years.

The herd has grown steadily since then. As of early 2026, over 100 bison graze across designated pastures within the prairie. They're managed as a conservation herd, meaning the focus is on genetic diversity and ecological impact rather than commercial production. Bison are natural prairie architects -- their grazing patterns, wallowing behavior, and movement create habitat diversity that benefits dozens of other species.

Best Tips for Seeing the Bison

• Bring binoculars or a spotting scope. The bison roam large pastures and aren't always close to the fence line. On some visits you'll spot them easily; other days they're distant specks.
• Try early morning or late afternoon. The herd tends to be more active during cooler parts of the day, especially in summer.
• Head to the Iron Bridge Trailhead area. This is one of the closest publicly accessible points to the bison pastures.
• Stay behind the fencing. These are wild animals weighing up to 2,000 pounds. They're not aggressive under normal circumstances, but they're unpredictable. The fences exist for good reason.
• Spring calving season (April-May) is exciting. New calves appear each year, and watching them interact with the herd is genuinely memorable.

Trail Guide

Midewin's trail network accommodates hikers, runners, cyclists, and horseback riders depending on the route. None of the trails are paved, but most are well-maintained gravel or mowed grass paths. If you enjoy exploring trails across Will County, Midewin's options stand out for their length and solitude.

Twin Oaks Trail

This is the most popular trail at Midewin and a solid choice for a first visit. The loop runs about 4 miles through a mix of restored prairie and scattered oak groves. The surface is crushed limestone, so it drains well and stays manageable even after rain. Wildflower displays along this route peak in late May and June, with purple coneflower, black-eyed Susan, and prairie dock putting on a show. You'll likely spot red-tailed hawks overhead and hear meadowlarks calling from the grass. The trailhead has parking and a restroom.

Henslow Trail

Named after the Henslow's sparrow -- a grassland bird that nests at Midewin -- this trail runs roughly 5 miles and passes through some of the most actively restored sections of the prairie. The surface alternates between gravel and mowed grass. Birders favor this route because the habitat supports species that are genuinely hard to find elsewhere in northeastern Illinois: Henslow's sparrows, bobolinks, sedge wrens, and upland sandpipers all breed in these grasslands. It's quieter than Twin Oaks, and you might have long stretches entirely to yourself.

Drumlin Kames Trail

At about 6 miles, this is one of the longer loops and takes you through terrain shaped by glacial activity. Drumlins and kames are landforms left behind by retreating ice sheets -- low, rounded hills and gravel deposits that give this section of Midewin slightly more topographic variety than the surrounding flatland. The trail surface is mostly mowed grass, which can get muddy after heavy rain. Bring waterproof boots in spring. This route sees fewer visitors, which makes it a good pick if you want solitude.

Wildlife Beyond the Bison

The prairie restoration has brought back an impressive community of grassland species, many of which were declining across Illinois before Midewin existed.

Grassland Birds

Midewin is one of the most important grassland bird habitats in the upper Midwest. Species you can find here during breeding season include:

• Bobolinks -- males perform a bubbling flight song over the prairie in May and June. Hard to miss once you know the sound.
• Eastern Meadowlarks -- their clear, whistled song carries across the open grass. They perch on fence posts and tall forbs, making them relatively easy to spot.
• Upland Sandpipers -- an unusual shorebird that breeds in grasslands rather than beaches. Midewin is one of few reliable spots in the region.
• Northern Harriers -- these low-flying raptors cruise over the grass hunting voles and small birds. Watch for their distinctive white rump patch.
• Short-eared Owls -- present in winter, hunting at dusk over the open fields. Seeing one quartering the prairie at sunset is unforgettable.

Butterflies and Pollinators

The restored wildflower plantings support a diverse pollinator community. Monarch butterflies pass through during fall migration, nectaring on late-blooming asters and goldenrod. You'll also find swallowtails, fritillaries, and skippers throughout summer. Several native bee species have been documented using the prairie, and ongoing research tracks how pollinator populations respond to different restoration techniques.

Other Wildlife

White-tailed deer are common, particularly near the woodland edges. Coyotes patrol the grasslands year-round -- you're more likely to hear them than see them, especially at dawn. Thirteen-lined ground squirrels pop up along trail edges. In wetter areas, you might encounter painted turtles, green frogs, and the occasional great blue heron.

Seasonal Highlights

Spring (March - May)

The prairie wakes up gradually. Early wildflowers appear in April, with the big bloom hitting in May and June. Shooting stars, wild hyacinth, and pasque flowers are among the first to show. Bird migration peaks in May, and bison calving season adds another reason to visit. Trails can be muddy, so plan footwear accordingly.

Summer (June - August)

Peak wildflower season. The tall grasses reach their full height by August, and the prairie buzzes with insect activity. Mornings are the best time to visit -- summer afternoons get hot and humid with little shade available. Carry plenty of water and wear sun protection. Ticks are active, so check yourself after every visit.

Fall (September - November)

Prairie grasses turn golden and bronze, creating some of the best photography conditions of the year. Monarch migration passes through in September. The cooler temperatures make hiking comfortable again. Hawks migrate along the Illinois flyway, and you can sometimes spot large kettles of broad-winged hawks overhead.

Winter (December - February)

Don't write off winter visits. The prairie takes on an austere beauty when covered in frost or light snow. Birding can be excellent -- short-eared owls, rough-legged hawks, and northern harriers work the open fields. The bison are particularly photogenic against a snowy backdrop. Fewer visitors means you'll likely have the place to yourself. Dress in layers and watch for ice on trail surfaces.

Practical Information

Hours and Fees

Midewin is open daily from 4:00 AM to 10:00 PM. There's no entrance fee -- it's entirely free to visit. The Welcome Center, located along Route 53 south of Joliet, operates on a more limited schedule (typically weekdays and some Saturdays). Stop in for maps, restroom access, and to ask staff about current trail conditions and bison locations.

Getting There

The prairie sits south of Joliet along Illinois Route 53 (also marked as Route 53/Manhattan Road). The main entrance and Welcome Center are about 10 miles south of I-80. Multiple trailheads have their own parking areas, so check a map before you go to pick the access point closest to where you want to hike. From downtown Chicago, the drive takes roughly 60 to 75 minutes depending on traffic.

What to Bring

• Binoculars -- essential for bison viewing and birding
• Water and snacks -- there are no concessions on-site
• Sunscreen and a hat -- shade is almost nonexistent on the trails
• Sturdy footwear -- waterproof boots in spring, trail shoes otherwise
• Insect repellent -- ticks and mosquitoes are present from April through October
• A camera with a decent zoom -- wildlife keeps its distance

Rules and Etiquette

Pets are allowed on most trails but must stay on a leash at all times. Stay on designated trails -- some areas remain closed for remediation or wildlife management. Hunting is permitted in certain zones during specific seasons, so wear blaze orange if you're visiting during fall hunting periods. No camping, no fires, no motorized vehicles on trails.

Why Midewin Matters

Less than 1% of the original tallgrass prairie that once covered Illinois still exists. Most of it was plowed under for agriculture more than a century ago. Midewin represents one of the largest attempts to bring that ecosystem back. It won't ever look exactly like pre-settlement prairie -- the seed bank is different, the hydrology has been altered, some invasive species are persistent -- but it's a genuine effort to restore something that was nearly lost.

For Will County residents, Midewin is an extraordinary resource sitting right in our backyard. Whether you're a serious birder, a casual hiker, or someone who just wants to see a bison that isn't behind a zoo fence, it's worth the trip. Pack a lunch, bring your binoculars, and give yourself a few hours. You won't run out of things to see.