Mount Holmes, Mountain summit in the Gallatin Range, Yellowstone National Park, Wyoming, United States

Mount Holmes is a 3,150-metre summit in the Gallatin Range, forming the range's southernmost point in the northwest of Yellowstone National Park, Park County, Wyoming. Indian Creek, a tributary of the Gardner River, rises on its slopes, and a ranger station near the top monitors forest fires and weather.

Mount Holmes was first marked on a map in 1860 by US Army captain William Reynolds, who labeled it Gallatin. Until 1878 it was also regularly called Madison for its proximity to the Madison River. In 1878 geographer Henry Gannett and explorer William Holmes made the first ascent; Gannett renamed the peak Holmes after his climbing partner and friend.

The name honours William Holmes, the artist, cartographer and climber who reached the summit with Henry Gannett in 1878; Gannett named the peak after his friend and climbing companion. A ranger station near the top keeps a constant watch on forest fires and weather, and the Bannock Trail passes close to the mountain.

The ascent follows a 17.4 km route to the summit, so plan a full day on foot. The Bannock Trail passes near the mountain, and a ranger station sits just below the summit, monitoring fires and weather.

On clear days the summit offers views that stretch toward Hebgen Lake, Electric Peak, and the Absaroka Range far across the landscape. Visitors with exceptionally clear conditions may also glimpse the Teton Range along the distant horizon.