The pass is known for being treacherous in the wintertime due to the steep 8% grade and switchbacks on the north side facing Ouray, though the entire road is paved.
The lower part of the pass towards Ouray is blasted into near-vertical cliffs of quartzite hundreds of feet above Red Mountain Creek and the Uncompahgre River.
[2] The Red Mountain Mining District lies from the divide northward to Ironton Park, halfway down towards Ouray.
Headframes of the old workings are still visible from the highway, as are the remains of the three largest communities: Red Mountain Town, Ironton, and Guston.
[3][4] The sprawling Idarado Mine (Treasury Tunnel) continued digging until the 1970s, and reclamation of tailings is ongoing.