In Depth

Glaciers transformed the rolling hills and meandering streams of pre-Pleistocene Yosemite into the colossal landscape of the present. And although Indian tribes lived in the Yosemite area for thousands of years, the first non-Indian visit was probably made by the Joseph Walker expedition in 1833.

It was not until 1851, however, before the existence of the magnificent valley became well known. The Mariposa Battalion was sent to the area that year to extinguish an ongoing conflict between gold miners seeking their fortune and the resident American Indians. The battalion entered Yosemite Valley at Inspiration Point, and word of the land's beauty quickly spread.

To preserve it for posterity, Abraham Lincoln set aside the Mariposa grove of giant sequoias in the Yosemite Valley as the nation's first state park on June 30, 1864. John Muir, one of America's earliest and foremost naturalists and conservationists, tirelessly advocated federal park status for Yosemite Valley and its surroundings, and 26 years later, in 1890, Yosemite became a national park.

The park is much greater both in area and beauty than most people generally realize; Yosemite Valley actually comprises only a very small portion of park land. The territory above the rim of the valley is less celebrated principally because it is less well-known. However, 196 miles of primary roads and more than 800 miles of trails now make much of this mountain region easily accessible to both motorist and hiker.

The crest of the Sierra Nevada is the park's eastern boundary, and the two rivers that flow through the park—the Merced and Tuolumne—originate among the snowy peaks. The Merced River flows through Yosemite Valley, and the Tuolumne River carves a magnificent gorge through the northern half of the park. Though spectacular through most of the year, many of the park's famous waterfalls are often dry during the late summer months.

With the exception of the Tioga Pass Road portion of SR 120, the Glacier Point Road and the Mariposa Grove Road, all of which are closed late fall through early summer, all roads are open year-round; chains may be required at any time during winter months.

The road to Mirror Lake and Happy Isles, at the eastern end of Yosemite Valley, is closed to most cars but is served by a free shuttle bus. Southside Drive is one-way eastbound from Bridalveil Fall to Half Dome Village; Northside Drive is one-way westbound from the Yosemite Valley Lodge; and the road between Half Dome Village and Yosemite Village also is one-way westbound.