When hikers ask which trails in Illinois are worth a full day — or several — the conversation always circles back to the same handful of routes. Below we've ranked the ten longest hiking trails in Illinois by total mapped distance, drawing from the 9,472 trails OutsideAtlas currently tracks in the state. Each entry includes the distance, what makes the route distinctive, and an honest note on who should actually attempt it.
Illinois is mostly flat tallgrass prairie reshaped by agriculture — but Shawnee National Forest in the south and the canyon country at Starved Rock are dramatic exceptions. The River-to-River Trail carries most multi-day mileage; segments connect to the larger American Discovery Trail network. Spring and fall are best; summer is muggy and tick-heavy in the south; winter sees ice in Shawnee's sandstone canyons.
Our rankings here are data-driven — pulled from the 9,472 mapped entries OutsideAtlas tracks in Illinois — but the data has limits worth being honest about. OpenStreetMap distance tags are crowd-sourced and inconsistent. A route may appear longer or shorter than the official measurement, especially when long-distance trails (like state and national scenic trails) are tagged in segments rather than as a single relation.
The Ranking
Ranked from #1 to #8. Click through any entry for the full trail page — map, elevation profile, weather forecast, and direct OpenStreetMap source link.
#1. Federer’s Folly Trail
At 0.80 mi, Federer’s Folly Trail tops the list — a route built for hikers who plan in days, not hours. Expect 0.80 mi, compacted surface on a forgiving grade. Local trail-association reports tend to agree this is one of the better-maintained options in the area, which matters more on a hike of this length than on a quick walk. Plan as a multi-day if you're not used to single-push 20+ mile days; resupply or shuttle logistics matter here. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Federer’s Folly Trail trail page →Map, elevation profile, current weather, and OSM source.#2. OBT-2
At 0.20 mi, OBT-2 lands at #2 — a route built for hikers who plan in days, not hours. Expect 0.20 mi on a forgiving grade. The route is well documented in OpenStreetMap, which is what put it on our radar — community-mapped routes tend to be the ones that get hiked enough to stay open. Plan as a multi-day if you're not used to single-push 20+ mile days; resupply or shuttle logistics matter here. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the OBT-2 trail page →Map, elevation profile, current weather, and OSM source.#3. OBT-3
At 0.20 mi, OBT-3 lands at #3 — a route built for hikers who plan in days, not hours. Expect 0.20 mi on a forgiving grade. It earns its ranking on the data, but trail conditions can change quickly after storms or fire seasons, so verify before you commit a full day. Plan as a multi-day if you're not used to single-push 20+ mile days; resupply or shuttle logistics matter here. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the OBT-3 trail page →Map, elevation profile, current weather, and OSM source.#4. ADT - Illinois (South) - J - Seg 2
At 0.10 mi, ADT - Illinois (South) - J - Seg 2 lands at #4 — a route built for hikers who plan in days, not hours. Expect 0.10 mi on a forgiving grade. Compared to similar trails in Illinois, this route trades difficulty for either solitude or scenery — sometimes both. Plan as a multi-day if you're not used to single-push 20+ mile days; resupply or shuttle logistics matter here. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the ADT - Illinois (South) - J - Seg 2 trail page →Map, elevation profile, current weather, and OSM source.#5. ADT - Illinois (South) - J - Seg 3
At 0.10 mi, ADT - Illinois (South) - J - Seg 3 lands at #5 — a route built for hikers who plan in days, not hours. Expect 0.10 mi on a forgiving grade. What makes this one earn its spot on the list is the combination of mapped detail and the kind of through-and-through experience that justifies a longer drive. Plan as a multi-day if you're not used to single-push 20+ mile days; resupply or shuttle logistics matter here. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the ADT - Illinois (South) - J - Seg 3 trail page →Map, elevation profile, current weather, and OSM source.#6. ADT - Indiana (North) - G - Seg 3
At 0.10 mi, ADT - Indiana (North) - G - Seg 3 lands at #6 — a route built for hikers who plan in days, not hours. Expect 0.10 mi on a forgiving grade. Local trail-association reports tend to agree this is one of the better-maintained options in the area, which matters more on a hike of this length than on a quick walk. Plan as a multi-day if you're not used to single-push 20+ mile days; resupply or shuttle logistics matter here. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the ADT - Indiana (North) - G - Seg 3 trail page →Map, elevation profile, current weather, and OSM source.#7. ADT - Iowa - K - Seg 1
At 0.10 mi, ADT - Iowa - K - Seg 1 lands at #7 — a route built for hikers who plan in days, not hours. Expect 0.10 mi on a forgiving grade. The route is well documented in OpenStreetMap, which is what put it on our radar — community-mapped routes tend to be the ones that get hiked enough to stay open. Plan as a multi-day if you're not used to single-push 20+ mile days; resupply or shuttle logistics matter here. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the ADT - Iowa - K - Seg 1 trail page →Map, elevation profile, current weather, and OSM source.#8. ADT - Missouri - L - Seg 2
At 0.10 mi, ADT - Missouri - L - Seg 2 lands at #8 — a route built for hikers who plan in days, not hours. Expect 0.10 mi on a forgiving grade. It earns its ranking on the data, but trail conditions can change quickly after storms or fire seasons, so verify before you commit a full day. Plan as a multi-day if you're not used to single-push 20+ mile days; resupply or shuttle logistics matter here. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the ADT - Missouri - L - Seg 2 trail page →Map, elevation profile, current weather, and OSM source.Planning your Illinois trip
A few pieces of context are worth keeping in mind specifically for Illinois. Spring and fall are best; summer is muggy and tick-heavy in the south; winter sees ice in Shawnee's sandstone canyons. Copperheads in the Shawnee uplands, ticks statewide, and flash floods in slot canyons after thunderstorms.
Always cross-reference the official land-manager page before driving out — closures, fire restrictions, and seasonal road access can change quickly. Our trail pages link directly back to the OpenStreetMap source so you can see the tags we're working from.
If you're new to hiking generally, our beginner's guide covers footwear, layering, and the day-pack basics. For safety planning on bigger objectives, the ten essentials guide is worth twenty minutes of reading.
More Illinois hiking guides
If you found this useful, the rest of our Illinois coverage continues below.
- Steepest trails in Illinois — Hikes with the most elevation gain in the state.
- Best beginner hikes in Illinois — Easy, well-marked trails for first-time hikers.
- Most challenging hikes in Illinois — Expert-rated routes for experienced hikers only.
- Best national parks in Illinois — Federal parks and recreation areas ranked.
- Best waterfall hikes in Illinois — Trails leading to named falls, ranked by accessibility.
- Best dog-friendly hikes in Illinois — Where leashed dogs are explicitly welcome.
- Best family hikes in Illinois — Short, easy trails sized for kids and grandparents.
Rankings like this are starting points, not verdicts. Trail conditions change, new routes get tagged, and what was the toughest trail in Illinois last year might not be next year. We refresh these articles when the underlying data shifts meaningfully.
Got a correction, a route we missed, or a question? Drop us a note via the contact page. We read every email and we'd rather hear it from you than miss it.
