When hikers ask which trails in Montana 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 Montana by total mapped distance, drawing from the 6,170 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.
Montana ranges from the Northern Rockies' glacier-carved peaks (Glacier NP, Bob Marshall Wilderness) to the rolling Great Plains east of the divide. The CDT and Pacific Northwest Trail both cross Montana; the Beartooth Plateau and Bob Marshall traverses are classic multi-day routes. Late June through mid-September is the high-country window; afternoon thunderstorms and grizzly activity are routine.
Our rankings here are data-driven — pulled from the 6,170 mapped entries OutsideAtlas tracks in Montana — 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 #10. Click through any entry for the full trail page — map, elevation profile, weather forecast, and direct OpenStreetMap source link.
#1. Blackfoot River Bridge
Blackfoot River Bridge earns the #1 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect 3,258 ft of gain 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 Blackfoot River Bridge trail page →Map, elevation profile, current weather, and OSM source.#2. Lewis and Clark Bridge
Lewis and Clark Bridge earns the #2 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect 1,965 ft of gain 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 Lewis and Clark Bridge trail page →Map, elevation profile, current weather, and OSM source.#3. Purple Mountain Trail
Purple Mountain Trail earns the #3 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect 2 ft of gain 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 Purple Mountain Trail trail page →Map, elevation profile, current weather, and OSM source.#4. Marco Flat Bridge
Marco Flat Bridge earns the #4 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect 3,268 ft of gain on a forgiving grade. Compared to similar trails in Montana, 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 Marco Flat Bridge trail page →Map, elevation profile, current weather, and OSM source.#5. Milk River Bridge
Milk River Bridge earns the #5 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect 2,224 ft of gain 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 Milk River Bridge trail page →Map, elevation profile, current weather, and OSM source.#6. Ptarmigan Tunnel
Ptarmigan Tunnel earns the #6 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect 7,100 ft of gain 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 Ptarmigan Tunnel trail page →Map, elevation profile, current weather, and OSM source.#7. Nez Perce (Nee Mee Poo) National Historic Trail
Nez Perce (Nee Mee Poo) National Historic Trail earns the #7 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect ground surface 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. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. 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 Nez Perce (Nee Mee Poo) National Historic Trail trail page →Map, elevation profile, current weather, and OSM source.#8. North Fork Badger-Goat Mountain Connector Trail
North Fork Badger-Goat Mountain Connector Trail earns the #8 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect ground surface 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. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. 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 North Fork Badger-Goat Mountain Connector Trail trail page →Map, elevation profile, current weather, and OSM source.#9. CDT -a-XX Continental Divide Trail Misc Alernate Old Routes
CDT -a-XX Continental Divide Trail Misc Alernate Old Routes earns the #9 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Tagged hard in OpenStreetMap. Compared to similar trails in Montana, 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 CDT -a-XX Continental Divide Trail Misc Alernate Old Routes trail page →Map, elevation profile, current weather, and OSM source.#10. Haystack Mountain National Recreation Trail
Haystack Mountain National Recreation Trail earns the #10 spot for its sheer distance, though the exact mileage in OpenStreetMap data is a rough estimate. Expect ground surface 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. The natural-surface tread can get slick after rain and muddy in spring — pick a dry weather window if you have the flexibility. 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 Haystack Mountain National Recreation Trail trail page →Map, elevation profile, current weather, and OSM source.Planning your Montana trip
A few pieces of context are worth keeping in mind specifically for Montana. Late June through mid-September is the high-country window; afternoon thunderstorms and grizzly activity are routine. Grizzly bears (carry spray, know how to use it), unbridged stream crossings, and lightning on exposed ridges are the recurring 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 Montana hiking guides
If you found this useful, the rest of our Montana coverage continues below.
- Steepest trails in Montana — Hikes with the most elevation gain in the state.
- Best beginner hikes in Montana — Easy, well-marked trails for first-time hikers.
- Most challenging hikes in Montana — Expert-rated routes for experienced hikers only.
- Best national parks in Montana — Federal parks and recreation areas ranked.
- Best waterfall hikes in Montana — Trails leading to named falls, ranked by accessibility.
- Best dog-friendly hikes in Montana — Where leashed dogs are explicitly welcome.
- Best family hikes in Montana — 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 Montana 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.
