The Fins
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The Fins

Idaho's best-kept secret — elite limestone sport climbing near Arco

About The Fins

The Fins is rapidly becoming one of the premier sport climbing destinations in the Intermountain West. Rows of razor-thin limestone ridges (the "fins") rise from the high desert near Arco, offering hundreds of bolted routes on steep, pocketed, and featured limestone. The crag is Idaho's answer to Rifle or Maple Canyon — technical, powerful, and steeply athletic. The concentration of 5.12–5.14 routes makes this a destination for elite climbers. The setting — angular rock fins against volcanic desert — is unlike anything else in Idaho.

Why Climb Here

  • Densest concentration of 5.12–5.14 routes in Idaho
  • Unique volcanic fin geology unlike any crag in the region
  • Near Craters of the Moon National Monument — combine both in one trip
  • Uncrowded even on weekends — still under the radar

Area Stats

Routes250+
Grade Range5.10–5.14d
Height40–120 ftft
Best SeasonApril, May, September, October
Day Use FeeFree — BLM land

Getting There

From Boise: 2.5 hours northeast via I-84 and US-20

Dirt road from Arco. High-clearance recommended in wet conditions.

Season

Best

April, May, September, October

Avoid

June, July, August

High desert heat makes summer miserable. North-facing fins stay cooler. Best conditions are spring and fall.

The Fins Gear Kit

Everything you need for a day of bolted sport climbing at City of Rocks, Massacre Rocks, or Black Cliffs.

Shop The Fins Gear at REI →

Lodging Near The Fins

Find Lodging at Booking.com →

Affiliate link — helps fund this guide