History of the Yosemite Region: Handbook of Yosemite National Park
Kuykendall RS. 1921. History of the Yosemite Region: Handbook of Yosemite National Park
It is probable that the first white men to look upon Yosemite Valley were members of the Joseph R. Walker expedition of 1833, which descended the western slope of the Sierra Nevada along the ridge between the Merced and the Tuolumne rivers. But the best contemporary evidence makes it clear that this party did not go down into the Valley. There are vague reports of hunters having entered the Valley as early as 1844, but the effective discovery of the Yosemite was made in 1851 by members of the Mariposa Battalion while in pursuit of hostile Indians.