Mount Whitney (Paiute: Too-man-i-goo-yah[6] or Too-man-go-yah[7]) is the highest mountain in the contiguous United States, with an elevation of 14,505 feet (4,421 m).

[9] The mountain's west slope is in Sequoia National Park and the summit is the southern terminus of the John Muir Trail, which runs 211.9 mi (341.0 km) from Happy Isles in Yosemite Valley.

Historically, during very wet years, water overflowed from the Tulare Basin into the San Joaquin River, which flows to the Pacific Ocean.

Based on the range from the highest average high of 25.7 °F (−3.5 °C) to the lowest average low of 4.2 °F (−15.4 °C) for winter temperatures in the table (December to March), every 1 inch (25 mm) of liquid precipitation equates to approximately 15–40 inches (380–1,020 mm) of snow, with lower temperatures producing the greater snow depths.

[15] The raising of Whitney (and the downdrop of the Owens Valley) is due to the same geological forces that cause the Basin and Range Province: the crust of much of the intermontane west is slowly being stretched.

[21] In Cretaceous time, masses of molten rock that originated from subduction rose underneath what is now Whitney and solidified underground to form large expanses of granite.

[21] In the last 2 to 10 million years, the Sierra was pushed up, enabling glacial and river erosion to strip the upper layers of rock to reveal the resistant granite that makes up Mount Whitney today.

[23] On August 18, 1873, Charles Begole, A. H. Johnson, and John Lucas, all of nearby Lone Pine, had become the first to reach the contiguous United States' highest summit.

[5] In 1881, Smithsonian Astrophysical Observatory founder Samuel Pierpont Langley remained on the summit for some time, making daily observations of the solar heat.

[25] In his memoirs,[26] Wallace wrote, "The Pi Ute [Paiute] Indians called Mount Whitney Too-man-i-goo-yah, which means 'the very old man.'

Despite losing out on their preferred name, Lone Pine residents financed the first trail to the summit, engineered by Gustave Marsh, and completed on July 22, 1904.

Having hiked the trail, U.S. Bureau of Fisheries employee Byrd Surby was struck and killed by lightning while eating lunch on the summit.

[28] A movement began after World War II to rename the mountain for Winston Churchill,[29] but the name Mount Whitney persisted.

The Mountaineer's Route, a gully on the north side of the east face first climbed by John Muir, is considered a scramble, class 3 (PD+).

[33] The fastest recorded time up this route to the summit and back to the portal is 3 hours 10 minutes, by Jason Lakey of Bishop, California.