Mount Sill, Mountain peak in Sierra Nevada, California.

Mount Sill is a granite peak in the Sierra Nevada of California, rising to about 14,150 feet (4,310 m) above sea level. It connects to the nearby North Palisade by way of a high rocky ridge, with steep faces dropping sharply on multiple sides.

The mountain's English name was coined in 1904 by mountaineer Joseph LeConte in honor of American poet Edward Rowland Sill. The Northern Paiute call it Nen-i-mish, "the Guardian of the Valley." The summit was first reached on July 24, 1903, by a party that included James Hutchinson and Joseph LeConte.

The Northern Paiute call the mountain Nen-i-mish, "the Guardian of the Valley". Its English name was coined in 1904 by mountaineer Joseph LeConte in honour of the American poet Edward Rowland Sill. The peak stands on the Sierra Crest where the crest turns sharply, so its summit looks over Kings Canyon National Park on one side and the John Muir Wilderness of Inyo National Forest on the other.

Routes to the summit range from scrambling paths to technical climbs that call for ropes and climbing gear. The window with the most stable conditions runs through the summer months, when snow on the upper sections has largely melted.

The mountain's Northern Paiute name, Nen-i-mish, means "the Guardian of the Valley". Its English name was coined in 1904 by mountaineer Joseph LeConte in honor of the American poet Edward Rowland Sill. The peak sits 0.6 miles (1 km) east of North Palisade, the high point of the Palisades group.