Climbing Slumgullion Pass northbound on Highway 149 is a journey into the heart of the rugged San Juan Mountains, notorious for its challenging gradients and stunning high-alpine scenery. You'll ascend through beautiful, remote forests for approximately 7-8 miles, gaining over 2,100 ft to reach the lofty 11,530 ft summit. This is a tough climb, averaging a steep 6% or more, but be particularly prepared for its well-known steepness: the hardest mile averages near 9.3%, with sustained pitches that can push 12-14% or even steeper. Enjoy the wild beauty and solitude as you wind your way up this paved scenic byway.