Rail trail · Illinois
Tunnel Hill State Trail
A 45-mile rail-trail through deep southern Illinois forest and the Shawnee Hills, featuring the historic 543-foot Tunnel Hill railroad tunnel and dozens of towering wooden trestles over the rugged Cache River watershed.
Length
45 miles
Surface
Crushed stone
Route
Point to point
Endpoints
Harrisburg to Karnak (near the Cache River State Natural Area)
Season
Best April through October; spring brings wildflowers and migrating birds; the tunnel and trestles are dramatic year-round but the trail surface may be soft after heavy rain
Plan your ride or walk
Tunnel Hill is one of the most scenic rail-trails in the Midwest, threading 45 miles through the rugged, forested Shawnee Hills of far southern Illinois. The trail's signature is the 543-foot-long hand-dug railroad tunnel near the village of Tunnel Hill, a cool, dark passage that riders and hikers walk through year-round. Beyond the tunnel, the trail crosses more than two dozen wooden trestles spanning ravines and wetlands above the Cache River watershed, a globally significant bottomland forest ecosystem. The crushed-limestone surface suits hybrid bikes and comfortable walking shoes. The southern end near Karnak connects to the Cache River State Natural Area, where bald cypress trees draped in Spanish moss create scenery more evocative of Louisiana than Illinois.
Getting there
The northern trailhead is in Harrisburg off Highway 45, about 2.5 hours southeast of St. Louis. The most-photographed access point is the Tunnel Hill village trailhead, about halfway along the route. The southern trailhead at Karnak is near the Cache River State Natural Area. Illinois does not currently charge a trail use fee.
Official trail information
Confirm current conditions, closures, and any required trail pass on the managing agency’s page.
Illinois DNR: Tunnel Hill State TrailWhat to bring
Gear keyed to a long, flat trail day: footwear, hydration, sun protection, and a pack sized for the distance.
Frequently asked questions
What is the Tunnel Hill tunnel?
The Tunnel Hill tunnel is a 543-foot-long hand-dug railroad tunnel cut through a ridge in the Shawnee Hills. It is wide enough to ride through, though the interior is unlit, so bringing a light is recommended. The tunnel stays cool year-round.
How long is Tunnel Hill State Trail?
The trail runs 45 miles point to point from Harrisburg in the north to Karnak near the Cache River State Natural Area in the south. Most visitors choose a segment around the Tunnel Hill village area for the tunnel and trestle highlights.
How many trestles are on the Tunnel Hill State Trail?
The trail crosses more than two dozen wooden trestles, some quite high above ravines and wetlands. The trestles are a major draw for photographers and add drama to an already scenic route through the Shawnee Hills.
What is the surface of the Tunnel Hill State Trail?
The trail is surfaced in crushed limestone throughout. It is suitable for hybrid and mountain bikes, and comfortable for walking. The surface can be soft after heavy rain, so check conditions before visiting during wet periods.
More Illinois trails
Looking for parks instead? Browse state parks by state.