If you've already worked your way through the Idaho day-hike checklist, this is the list for what comes next. We ranked the state's hardest trails using a composite of difficulty tag (hard or expert), distance, and elevation gain, drawing from the 8,053 mapped Idaho trails in our database. These ten routes are reserved for hikers with the gear, the navigation skills, and the honesty about their own limits to tackle them safely.
Idaho is more mountainous than its neighbors realize — the Sawtooths, Bitterroots, and Lost River Range carry alpine terrain rivaling Colorado in remoteness if not raw elevation. The Sawtooth Wilderness loop, the full CDT panhandle section, and Hells Canyon rim-to-river all qualify as elite undertakings. Grizzly bears in the Greater Yellowstone region (eastern Idaho), forest fires in late summer, and major stream crossings on backcountry routes are the standard concerns.
Our rankings here are data-driven — pulled from the 8,053 mapped entries OutsideAtlas tracks in Idaho — but the data has limits worth being honest about. A composite score weights expert and hard difficulty tags alongside total mileage and elevation gain. The result favors long, vertically aggressive routes with documented technical sections — there are surely tougher off-trail objectives in the state, but those are outside the scope of a trail directory.
The Ranking
Ranked from #1 to #10. Click through any entry for the full trail page — map, elevation profile, weather forecast, and direct OpenStreetMap source link.
#1. State Line (Granite Peak)
State Line (Granite Peak) sits near Alberton in Mineral County and is rated expert — our pick for the toughest trail on the list. Tagged expert in OpenStreetMap. 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. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the State Line (Granite Peak) trail page →Map, elevation profile, current weather, and OSM source.#2. State Line (Granite Peak)
State Line (Granite Peak) sits near Alberton in Missoula County and is rated expert — the #2 entry in a roster of hikes you don't take lightly. Tagged expert in OpenStreetMap. 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. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the State Line (Granite Peak) trail page →Map, elevation profile, current weather, and OSM source.#3. Valley Creek 1300 path
Valley Creek 1300 path sits near Frenchtown in Sanders County and is rated expert — the #3 entry in a roster of hikes you don't take lightly. Expect ground surface on a expert-only 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. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Valley Creek 1300 path trail page →Map, elevation profile, current weather, and OSM source.#4. Valley Creek 1300 section of heavey alder
Valley Creek 1300 section of heavey alder sits near Frenchtown in Sanders County and is rated expert — the #4 entry in a roster of hikes you don't take lightly. Expect ground surface on a expert-only grade. Compared to similar trails in Idaho, this route trades difficulty for either solitude or scenery — sometimes both. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Valley Creek 1300 section of heavey alder trail page →Map, elevation profile, current weather, and OSM source.#5. Antoine Summit Trail
Antoine Summit Trail sits near Otis Orchards in Spokane County and is rated hard — the #5 entry in a roster of hikes you don't take lightly. Tagged hard in OpenStreetMap. 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. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Antoine Summit Trail trail page →Map, elevation profile, current weather, and OSM source.#6. Brennan
Brennan sits near Kimberly in Twin Falls County and is rated hard — the #6 entry in a roster of hikes you don't take lightly. Expect dirt surface on a genuinely demanding 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. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Brennan trail page →Map, elevation profile, current weather, and OSM source.#7. Brennan
Brennan sits near Kimberly in Twin Falls County and is rated hard — the #7 entry in a roster of hikes you don't take lightly. Expect dirt surface on a genuinely demanding 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. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Brennan trail page →Map, elevation profile, current weather, and OSM source.#8. Brennan
Brennan sits near Kimberly in Twin Falls County and is rated hard — the #8 entry in a roster of hikes you don't take lightly. Expect dirt surface on a genuinely demanding 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. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Brennan trail page →Map, elevation profile, current weather, and OSM source.#9. Brennan
Brennan sits near Kimberly in Twin Falls County and is rated hard — the #9 entry in a roster of hikes you don't take lightly. Expect dirt surface on a genuinely demanding grade. Compared to similar trails in Idaho, this route trades difficulty for either solitude or scenery — sometimes both. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Brennan trail page →Map, elevation profile, current weather, and OSM source.#10. Brennan
Brennan sits near Kimberly in Twin Falls County and is rated hard — the #10 entry in a roster of hikes you don't take lightly. Expect dirt surface on a genuinely demanding 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. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. Best attempted by hikers comfortable with long days, route-finding when the path gets faint, and weather that can turn fast. Not a casual outing. See full trail details, map, and current weather on OutsideAtlas for the most current information.
Open the Brennan trail page →Map, elevation profile, current weather, and OSM source.Planning your Idaho trip
A few pieces of context are worth keeping in mind specifically for Idaho. July through September is the high-country window; lower-elevation desert hiking (City of Rocks) extends April-October. Grizzly bears in the Greater Yellowstone region (eastern Idaho), forest fires in late summer, and major stream crossings on backcountry routes are the standard concerns.
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 Idaho hiking guides
If you found this useful, the rest of our Idaho coverage continues below.
- Top 10 longest trails in Idaho — Multi-day routes and through-hikes ranked by distance.
- Steepest trails in Idaho — Hikes with the most elevation gain in the state.
- Best beginner hikes in Idaho — Easy, well-marked trails for first-time hikers.
- Best national parks in Idaho — Federal parks and recreation areas ranked.
- Best waterfall hikes in Idaho — Trails leading to named falls, ranked by accessibility.
- Best dog-friendly hikes in Idaho — Where leashed dogs are explicitly welcome.
- Best family hikes in Idaho — 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 Idaho 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.
