Mount Index

Mount Index is a peak in the central part of the Cascade Range of Washington state. It lies just south of the Skykomish River and U.S. Route 2, at the western edge of the Cascades. Despite its low elevation relative to peaks higher in the Cascades, it is a famous and dramatic landmark due to its topographic prominence. It comprises three pointed spires which rise steeply from a very low base. The main peak is the southernmost of the three, while the North Peak rises even more steeply above the valley. For example, it rises more than 4,250 ft (1,300 m) above the lower slopes on the northeast side in less than 1 horizontal mile (1.6 km).

The first recorded ascent of Mount Index (the main peak) was on October 29, 1911, by H. B. Hinman, Ernest Martin, Lee Pickett, George E. Wright. However, they found a flagpole already on the summit, so theirs was certainly not the first ascent. A much earlier ascent by Native Americans is likely. The first ascent of the steeper, more difficult North Peak was in 1929, by Lionel Chute and Victor Kaartinen, by the North Face Route.

The standard route on the main peak climbs the east side of the peak from Lake Serene. The standard route on the North Peak is the North Face Route, which is a long, moderately technical climb (Grade III, Class 5.6).

Mount Index was once known as West Index Mountain, and Baring Mountain was known as Mount Index instead. They were both renamed in 1917.