The most technically committing of the three Chicago Basin fourteeners, featuring a famous exposed ledge traverse known as the Catwalk.
Access is via the Durango & Silverton Narrow Gauge Railroad to the Needleton stop (advance ticket required), followed by a roughly 6-mile, 2,800–2,900-foot backpack up the Needle Creek Trail into Chicago Basin, where most parties camp for multiple days. From a Chicago Basin camp, climb toward Twin Lakes and then the saddle between Eolus and North Eolus. From the saddle, follow the exposed but non-technical Catwalk — a narrow ridge with real drop-offs on both sides — southwest to Eolus's summit at 14,083 feet. Many parties tag neighboring North Eolus from the same saddle in the same outing.
Reverse the Catwalk and ridge back to camp. Wait for dry, calm conditions before attempting the Catwalk — it is far more consequential in wind, rain, or snow.