Four Mile Trail is a moderate to strenuous trail leading from Yosemite Valley to Glacier Point. The trail begins at the valley floor west of the Swinging Bridge recreation area, and climbs the south side 4.8 miles (7.7 km) up to Glacier Point, an elevation change of 3,200 feet (1,000 m).

http://en.wikipedia.org/wiki/Four_Mile_Trail