If you've already worked your way through the Colorado 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 17,956 mapped Colorado 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.
Colorado is the highest-elevation US state — 58 peaks above 14,000 feet, deep glacial valleys, and the Continental Divide running its full length. The Maroon Bells traverse, Capitol Peak's knife edge, and full CT thru-hikes represent Colorado's elite tier. Lightning above treeline is the leading hazard — plan to be off summits by noon. Altitude sickness hits hikers from sea level on any 12,000+ ft outing.
Our rankings here are data-driven — pulled from the 17,956 mapped entries OutsideAtlas tracks in Colorado — 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. Barr Trail
Barr Trail sits near Cascade in El Paso County and is rated expert — our pick for the toughest trail on the list. Expect ground surface on a expert-only 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 Barr Trail trail page →Map, elevation profile, current weather, and OSM source.#2. Big Marvine Peak Trail
Big Marvine Peak Trail sits near Burns in Rio Blanco County and is rated expert — the #2 entry in a roster of hikes you don't take lightly. Expect ground surface on a expert-only 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 Big Marvine Peak Trail trail page →Map, elevation profile, current weather, and OSM source.#3. BLM Trail T6101A
BLM Trail T6101A sits near Penrose in Fremont County and is rated expert — the #3 entry in a roster of hikes you don't take lightly. Expect unpaved 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. A paved surface makes this one of the more accessible options on the list — good for strollers, mobility aids, and wet-weather days. 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 BLM Trail T6101A trail page →Map, elevation profile, current weather, and OSM source.#4. Bootlegger Gulch Trail
Bootlegger Gulch Trail sits near Rico in Montezuma 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 Colorado, 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 Bootlegger Gulch Trail trail page →Map, elevation profile, current weather, and OSM source.#5. Captain Morgans
Captain Morgans sits near Colorado Springs in El Paso County and is rated expert — the #5 entry in a roster of hikes you don't take lightly. Expect ground surface on a expert-only 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 Captain Morgans trail page →Map, elevation profile, current weather, and OSM source.#6. Carbon Trail 436
Carbon Trail 436 sits near Crested Butte in Gunnison County and is rated expert — the #6 entry in a roster of hikes you don't take lightly. Expect ground surface on a expert-only 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 Carbon Trail 436 trail page →Map, elevation profile, current weather, and OSM source.#7. Carbon Trail 436
Carbon Trail 436 sits near Crested Butte in Gunnison County and is rated expert — the #7 entry in a roster of hikes you don't take lightly. Expect ground surface on a expert-only 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 Carbon Trail 436 trail page →Map, elevation profile, current weather, and OSM source.#8. Chiquita Mountain Bypass
Chiquita Mountain Bypass sits near Estes Park in Larimer County and is rated expert — the #8 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 Chiquita Mountain Bypass trail page →Map, elevation profile, current weather, and OSM source.#9. Dakota Ridge South Trail
Dakota Ridge South Trail sits near Idledale in Jefferson County and is rated expert — the #9 entry in a roster of hikes you don't take lightly. Expect dirt surface on a expert-only grade. Compared to similar trails in Colorado, 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 Dakota Ridge South Trail trail page →Map, elevation profile, current weather, and OSM source.#10. Dakota Ridge South Trail
Dakota Ridge South Trail sits near Idledale in Jefferson County and is rated expert — the #10 entry in a roster of hikes you don't take lightly. Expect dirt surface on a expert-only 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 Dakota Ridge South Trail trail page →Map, elevation profile, current weather, and OSM source.Planning your Colorado trip
A few pieces of context are worth keeping in mind specifically for Colorado. Summer (mid-June through September) is the practical window for high routes; afternoon thunderstorms are reliable July-August. Lightning above treeline is the leading hazard — plan to be off summits by noon. Altitude sickness hits hikers from sea level on any 12,000+ ft outing.
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 Colorado hiking guides
If you found this useful, the rest of our Colorado coverage continues below.
- Top 10 longest trails in Colorado — Multi-day routes and through-hikes ranked by distance.
- Steepest trails in Colorado — Hikes with the most elevation gain in the state.
- Best beginner hikes in Colorado — Easy, well-marked trails for first-time hikers.
- Best national parks in Colorado — Federal parks and recreation areas ranked.
- Best waterfall hikes in Colorado — Trails leading to named falls, ranked by accessibility.
- Best dog-friendly hikes in Colorado — Where leashed dogs are explicitly welcome.
- Best family hikes in Colorado — 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 Colorado 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.
