The hardest hikes in Colorado, by the numbers
Of the 722 trails in Colorado in our dataset, 195 (27 percent) rate strenuous or very strenuous on the gain-and-distance scale we use and run 3 to 30 miles with at least 1,500 ft of climb; these are the 25 with the highest rating.
Chicago Basin 14er Grand Slam leads with 12,167 ft of gain over 28.9 miles, 421 ft per mile, with a steepest pitch of 68 percent.
Across the 25, gain runs from 3,911 to 12,167 ft and distance from 12.5 miles to 29.2 miles; the median gain is 5,337 ft and the median distance 21.3 miles.
11 of the 25 are point-to-point routes; the rest are out-and-back (4) or loop (10).
| # | Trail | Miles | Gain (ft) | Ft per mile | Max grade | Elevation (ft) | Rating | Profile |
|---|---|---|---|---|---|---|---|---|
| 1 | Chicago Basin 14er Grand SlamSouthwest Rockies | 28.9 | 12,167 | 421 | 68% | 8,198 to 13,935 | 838.6 | |
| 2 | Four Pass LoopCentral Rockies | 27.1 | 7,327 | 270 | 54% | 9,571 to 12,454 | 630.2 | |
| 3 | Lost Creek Wilderness LoopCentral Rockies | 29.2 | 6,156 | 211 | 45% | 8,078 to 10,890 | 599.6 | |
| 4 | Pawnee-Buchanan LoopFront Range | 26.5 | 6,632 | 250 | 42% | 8,820 to 12,528 | 592.9 | |
| 5 | Georgia Pass to Argentine Pass | 22.1 | 6,930 | 314 | 56% | 10,423 to 13,247 | 553.4 | |
| 6 | Devils Playground to Barr TrailFront Range | 18.9 | 7,397 | 391 | 69% | 6,741 to 14,102 | 528.8 | |
| 7 | Rito Alto Four Pass LoopSouthwest Rockies | 23 | 5,843 | 254 | 40% | 9,056 to 13,004 | 518.4 | |
| 8 | Ten-Mile Range TraverseCentral Rockies | 19 | 7,047 | 371 | 72% | 9,099 to 13,614 | 517.5 | |
| 9 | Grand Lake to Bowen GulchRocky Mountain NP | 28.3 | 4,411 | 156 | 33% | 8,377 to 12,209 | 499.7 | |
| 10 | Snowmass - Willow Lake LoopCentral Rockies | 22.3 | 5,436 | 244 | 34% | 8,396 to 12,669 | 492.4 | |
| 11 | Longs Peak Valley LoopRocky Mountain NP | 23.2 | 5,129 | 221 | 71% | 8,551 to 12,060 | 487.8 | |
| 12 | Mummy Kill RouteRocky Mountain NP | 16.7 | 7,004 | 419 | 51% | 8,568 to 13,350 | 483.7 | |
| 13 | Herman's Gulch to Berthoud Pass | 21.6 | 5,034 | 233 | 43% | 10,323 to 13,200 | 466.3 | |
| 14 | James Peak to Rollins Pass LoopFront Range | 21.3 | 4,886 | 229 | 42% | 9,216 to 13,248 | 456.2 | |
| 15 | North Inlet / Tonohutu Creek LoopRocky Mountain NP | 26.6 | 3,911 | 147 | 34% | 8,485 to 12,208 | 456.1 | |
| 16 | Barr TrailFront Range | 12.5 | 7,545 | 604 | 36% | 6,509 to 14,051 | 434.3 | |
| 17 | Upper Slate LakeCentral Rockies | 22.7 | 4,091 | 180 | 35% | 9,071 to 10,896 | 431 | |
| 18 | Boulder Skyline TraverseFront Range | 17.3 | 5,345 | 309 | 56% | 5,425 to 8,433 | 430 | |
| 19 | Baker Gulch to Bowen LakeRocky Mountain NP | 19.9 | 4,483 | 225 | 41% | 8,844 to 12,113 | 422.4 | |
| 20 | Colorado Trail | 20.3 | 4,353 | 214 | 34% | 9,193 to 11,770 | 420.4 | |
| 21 | Capitol PeakCentral Rockies | 16 | 5,337 | 334 | 44% | 9,069 to 14,120 | 413.3 | |
| 22 | Bowen Gulch to Willow Creek PassRocky Mountain NP | 19.7 | 4,207 | 214 | 29% | 8,764 to 11,435 | 407.1 | |
| 23 | Longs Peak - Keyhole RouteRocky Mountain NP | 14 | 5,241 | 374 | 61% | 9,404 to 14,196 | 383.1 | |
| 24 | Hell Canyon LoopCentral Rockies | 17 | 4,221 | 248 | 47% | 8,291 to 11,837 | 378.8 | |
| 25 | Mount Elbert LoopCentral Rockies | 14.5 | 4,913 | 339 | 34% | 10,075 to 14,407 | 377.5 |
How this list is ranked
Rating = the square root of 2 x elevation gain (ft) x distance (miles), the gain-and-distance formula Shenandoah National Park publishes for its own trails. Bands: under 50 easiest, 50 to 100 moderate, 100 to 150 moderately strenuous, 150 to 200 strenuous, 200 and over very strenuous.
This list: band strenuous (150 to 200) or very strenuous (200 and over), 3 to 30 miles, at least 1,500 ft of gain, ordered by rating desc, gain per mile desc, capped at 25. The rating column is computed from the miles and gain printed in the same row, the numbers each trail page uses, so every row can be checked from the row itself. The rating says nothing about exposure, scrambling, altitude or conditions.
Only trails with a full page count, so "Colorado" here means the 722 trails in Colorado in our dataset, not every trail in Colorado.
Each trail page shows the full elevation profile behind these numbers and the same data drawn as a topographic print, made to order. Start with Chicago Basin 14er Grand Slam.
Hardest hikes elsewhere.
The same ranking for other states in our dataset.