🌤 Weather at Tunnel Hill State Trail by season
| Spring | Summer | Fall | Winter |
|---|---|---|---|
| 36–78 °F | 65–89 °F | 36–82 °F | 24–48 °F |
Each range runs from the coldest monthly average low to the warmest monthly average high in that season (1991-2020 climate normals), measured at Harrisburg, 2 mi away, elevation 365 ft. Conditions at the park can differ from the station, especially where elevation differs — check a forecast before you go.
Tunnel Hill State Trail is a public state park in Illinois near Harrisburg in Saline County County. The park offers a peaceful retreat into nature for visitors of all ages.
Quick Facts
| State | Illinois |
| Nearest City | Harrisburg |
| County | Saline County |
Location & Getting There
Tunnel Hill State Trail is located near Harrisburg, Illinois. The park’s coordinates are 37.7181516, -88.5457073.
Things to Do
Illinois state parks offer surprising geological diversity — from sandstone canyons and waterfalls in the south to prairie grasslands, river bluffs, and Great Lakes shoreline in the north. Popular activities include hiking through dramatic canyon formations at Starved Rock and Matthiessen, fishing for bass and catfish in the state’s rivers and lakes, camping in forested settings along the Illinois and Mississippi Rivers, biking paved and gravel trails, birdwatching along major migratory flyways (Illinois sits on the Mississippi Flyway), cross-country skiing in winter, horseback riding on dedicated equestrian trails, and exploring historic sites from frontier forts to Lincoln-era landmarks.
Best Time to Visit
Illinois parks shine across all four seasons. Spring (April–May) brings peak waterfall flow at Starved Rock and Matthiessen after snowmelt, plus wildflower carpets in the canyon floors. Summer (June–August) is ideal for swimming, Lake Michigan beaches, and river recreation — but canyon parks get crowded on weekends. Fall (September–November) delivers stunning foliage, especially in the southern Shawnee National Forest region, peaking mid-October. Winter transforms canyon parks into ice wonderlands — frozen waterfalls at Starved Rock are a major winter attraction. All Illinois state parks are free — no entrance fees or vehicle passes required.
Visitor Tips
All Illinois state parks offer free admission — there are no entrance fees or vehicle passes required. This makes Illinois one of the most visitor-friendly state park systems in the country. Camping fees are modest ($8–$35/night depending on amenities). Reservations are made through the Illinois DNR reservation system. Popular parks like Starved Rock fill parking lots before 9 AM on fall and spring weekends — arrive early. Many parks offer excellent lodge accommodations (Starved Rock Lodge, Pere Marquette Lodge, Giant City Lodge) for those who prefer indoor comfort with park access.
Explore More Illinois State Parks
Tunnel Hill State Trail is one of many outstanding state parks in Illinois. Discover more parks in our Best State Parks in Illinois guide, or use our Park Finder to search by activity, location, or features.
Wildlife & Nature
Tunnel Hill State Trail — a 45-mile rail-to-trail conversion — follows the route of the former Cairo & Vincennes Railroad through the Shawnee Hills of southern Illinois. The trail passes through a 543-foot tunnel built in 1871 — one of the longest rail-to-trail tunnels in the Midwest. The trail traverses some of the most biologically diverse landscape in Illinois — from the Cache River cypress swamps to the sandstone bluffs of the Shawnee Hills. Cyclists and hikers share the crushed limestone surface with wildlife — white-tailed deer, wild turkeys, and box turtles frequently cross the trail. Worm-eating warblers and hooded warblers sing from the forest. The tunnel provides habitat for Indiana bats — one of the most endangered mammals in North America.
Nearby Attractions
Vienna — the Johnson County seat — provides trail services. Cache River State Natural Area protects 1,000-year-old bald cypress and Ramsar wetlands. Garden of the Gods offers spectacular sandstone formations. Shawnee National Forest provides extensive recreation. Cave-in-Rock State Park has a famous Ohio River cave. Dixon Springs State Park has unique sandstone features. Golconda is a charming Ohio River community. Giant City State Park has massive “stone streets.”
Make it a road trip: Pair a visit with Saline County State Fish and Wildlife Area (a short drive away) or Sahara Woods (Illinois) (a short drive away).
🐾 Dogs & Pets at Tunnel Hill State Trail
- Pets allowed? statewide rule
- Pets are allowed in Illinois state parks and on trails as long as they are leashed at all times.
- Leash rule statewide rule
- Leash required at all times; state code caps leash length at 10 feet
- Beaches & swim areas statewide rule
- Pets are prohibited in areas posted 'NO PETS', reserved for beach areas, concession areas and crowded campground/picnic areas (e.g. no dogs on the beach at Illinois Beach State Park)
- Cabins & lodging statewide rule
- Pets are not allowed in campground cabins
- Statewide exceptions statewide rule
- Leash rule exceptions for hunting dogs, field trials and dog training areas; pets must not be left unattended
Are dogs allowed at Tunnel Hill State Trail?
Pets are allowed in Illinois state parks and on trails as long as they are leashed at all times. Individual parks can post stricter rules — check signage on arrival.
Rules verified July 2026 via dnr.illinois.gov. More: Illinois state parks guide · Dog rules in all 50 states compared
Park Location
Plan your gear for Tunnel Hill State Trail
From our editorial guides, matched to this park’s activities:
