Mount Isto, Mountain summit in Brooks Range, Alaska, US

Mount Isto is the highest peak in the Brooks Range, in the Romanzof Mountains of eastern Alaska, within the Arctic National Wildlife Refuge. It rises about 8,976 feet (2,736 m) and lies 5 miles (8.0 km) south of Mount Hubley, the range's second-highest summit.

The peak received its name in 1966 honoring Reynold E. Isto, a civil engineer who advanced Alaska's mapping efforts through helicopter survey work. This naming reflected broader initiatives to document key geographical landmarks across Arctic regions.

The peak lies within the Arctic National Wildlife Refuge, and its name, given in 1966, honours Reynold E. (Pete) Isto, a civil engineer with the U.S. Geological Survey. It stands 5 miles (8.0 km) south of Mount Hubley, the second-highest summit of the Brooks Range.

Access requires helicopter transport to remote tundra valleys since no roads lead to the base. From there, mountaineers must navigate steep ridges and glaciated terrain to reach the summit.

Advanced surveying technology confirmed in 2014 that this peak holds the rank of highest in the chain, surpassing earlier measurements of Mount Chamberlin. This reassessment showed how precise technology can correct previous geographical assumptions.