When hikers ask which trails in Colorado 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 Colorado by total mapped distance, drawing from the 17,956 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.
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 Colorado Trail and CDT carry most of the state's thru-hiking traffic; many segments are above 10,000 ft for days at a time. Summer (mid-June through September) is the practical window for high routes; afternoon thunderstorms are reliable July-August.
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. 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 #7. Click through any entry for the full trail page — map, elevation profile, weather forecast, and direct OpenStreetMap source link.
#1. ADT - Colorado A - O - Seg 3
At 0.20 mi, ADT - Colorado A - O - Seg 3 tops the list — a route built for hikers who plan in days, not hours. Expect 0.20 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 - Colorado A - O - Seg 3 trail page →Map, elevation profile, current weather, and OSM source.#2. ADT - Colorado B - P - Seg 1
At 0.10 mi, ADT - Colorado B - P - Seg 1 lands at #2 — 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 - Colorado B - P - Seg 1 trail page →Map, elevation profile, current weather, and OSM source.#3. ADT - Colorado B - P - Seg 2
At 0.10 mi, ADT - Colorado B - P - Seg 2 lands at #3 — 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 - Colorado B - P - Seg 2 trail page →Map, elevation profile, current weather, and OSM source.#4. ADT - Colorado C - Q - Seg 4
At 0.10 mi, ADT - Colorado C - Q - Seg 4 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 Colorado, 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 - Colorado C - Q - Seg 4 trail page →Map, elevation profile, current weather, and OSM source.#5. ADT - Colorado C - Q - Seg 5
At 0.10 mi, ADT - Colorado C - Q - Seg 5 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 - Colorado C - Q - Seg 5 trail page →Map, elevation profile, current weather, and OSM source.#6. ADT - Colorado C - Q - Seg 6
At 0.10 mi, ADT - Colorado C - Q - Seg 6 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 - Colorado C - Q - Seg 6 trail page →Map, elevation profile, current weather, and OSM source.#7. ADT - Utah - R - Seg 1
At 0.10 mi, ADT - Utah - R - 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 - Utah - R - Seg 1 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.
- 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.
- Most challenging hikes in Colorado — Expert-rated routes for experienced hikers only.
- 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.
