About 10 million years ago, the Sierra Nevada was uplifted and then tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, narrow canyons. About 1 million years ago, snow and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet (1,200 m) during the early glacial episode. The downslope movement of the ice masses cut and sculpted the U-shaped valley.
Yosemite Valley’s first recorded inhabitants were American Indians who called the Valley "Ah-wah-nee", meaning "dwellers in Ahwahnee," and called themselves the Ahwahnechee , perhaps 6,000 to 8,000 years ago. They gathered black oak acorns and hunted and fished in Yosemite Valley. They traded these and other commodities for obsidian, rabbit skins and pine nuts that came from the east side of the Sierra. They are related to the Northern Paiute and Mono tribes. Many tribes visited the area to trade, including nearby Central Sierra Miwoks, who lived along the drainage area of the Tuolumne and Stanislaus Rivers. A major trading route went over Mono Pass and through Bloody Canyon to Mono Lake, to the east of the Yosemite area. Vegetation and game in the region was similar to that present today; acorns were a staple to their diet, as well as other seeds and plants, salmon and deer. They annually burned the vegetation on the Valley floor, which promoted the black oak and kept the meadows and forests open. This protected the supply of their principal food, acorns, and reduced the chance of ambush. At the time of first European contact, this band was led by Chief Tenaya (Teneiya), who was raised by his mother among the Mono Lake Paiutes.
The Ahwahneechee lived here for generations, followed by the arrival of Europeans in the mid-1800s. The first non-natives to see Yosemite Valley were probably members of the 1833 Joseph Walker Party, which was the first to cross the Sierra Nevada from east to west.
The first descriptions of Yosemite, however, came nearly 20 years later. The 1849 California Gold Rush dramatically increased travel by European-Americans in the area, causing competition for resources between the regional Paiute and Miwok and the miners and hangers on. By 1851, the continued theft of Indian lands and murder of native people resulted in the Mariposa Indian War. On March 27, 1851, Major James D. Savage, whose trading post on the Merced River had been raided by the Awaneechee, was sent to suppress the Indians. Chief Tenaya and his Ahwahneechee were eventually captured and their village burned; they were removed to a reservation near Fresno. The chief and some others were later allowed to return to Yosemite Valley. In the spring of 1852 they attacked a group of eight gold miners, and then moved east to flee law enforcement. Near Mono Lake, they took refuge with the nearby Mono tribe of Paiute. They stole horses from their hosts and moved away, but the Mono Paiutes tracked down and killed many of the Ahwahneechee, including Chief Tenaya. The Mono Paiute took the survivors as captives back to Mono Lake and absorbed them into the Mono Lake Paiute tribe.
While the members of that first expedition of the Mariposa Battalion had heard rumors of what could be found up the Merced River, none were prepared for what they saw March 27, 1851 from what is now called Old Inspiration Point (close to Tunnel View). Camping that night on the Valley floor, the group agreed to call it "Yo-sem-i-ty", mistakenly believing that was the native name. The name "Yosemite" (meaning "killer" in Miwok) originally referred to the name of a renegade tribe which was driven out of the area (and possibly annihilated) by the Mariposa Battalion.
Knowledge of Yosemite’s beauty spread, and in 1855, the first tourists began to arrive. James Hutchings—who organized the first tourist party to the Valley in 1855—and artist Thomas Ayers generated much of the earliest publicity about Yosemite, creating articles and entire magazine issues about the Valley. Ayres' highly detailed angularly exaggerated artwork and his written accounts were distributed nationally and an art exhibition of his drawings was held in New York City. Two of Hutchings' first group of tourists, Milton and Houston Mann, built the first toll route into the valley, with development of the first hotels in the area and other trails quickly following. Orchards were planted and livestock grazed in Valley meadows, with damage to native ecosystems as the result.
During the Civil War, a group of influential Californians, wishing to protect the area, persuaded the U. S. Congress and President Abraham Lincoln to grant Yosemite Valley and the Mariposa Grove to the State of California as an inalienable public trust in June 1864.
Wawona was an Indian encampment in what is now the southwestern part of the park. Settler Galen Clark discovered the Mariposa Grove of giant sequoia in Wawona in 1857. He had simple lodgings built, and roads to the area. In 1879, the Wawona Hotel was built to serve tourists visiting Mariposa Grove. Due to the difficulty of traveling there, early visitors to the valley came for several weeks to a couple of months, often as entire families with many possessions. Early hotels such as the Wawona were therefore set up for extended stays and catered primarily to wealthy patrons who could spend extended periods away from home. As tourism increased, so did the number of trails and hotels developed by people intending to build on the trade.
The Wagon Tree, also known as the Tunnel Tree, was a famous giant sequoia that stood in the Mariposa Grove. It was 227 feet (69 m) tall, and was 90 ft (27 m) in circumference. When a carriage-wide tunnel was cut through the tree in 1881, it became even more popular as a tourist photo attraction. Everything from horse-drawn carriages in the late 19th century, to automobiles in the first part of the 20th century, traveled the road which passed through that tree. The Wawona Tree fell in 1969 under a heavy load of snow. It was estimated to have been 2,300 years old.
The rugged terrain challenged many early European travelers, with just a few—only 650 from the mid-1850s to mid-1860s—making the journey to Yosemite Valley by horseback or stage. By 1907, construction of the Yosemite Valley Railroad from Merced to El Portal eased the journey, thereby, increasing visitation.
By late 1860s, the surrounding high country became overrun with overgrazing by domestic sheep which were destroying vegetation and depleting the beauty of the landscape by logging of giant sequoias. John Muir arrived in California in 1868. He and Robert Johnson, editor of Century Magazine, started a movement to protect the high country and campaigned to make Yosemite Valley into a national park.
President Abraham Lincoln signed a bill on June 30, 1864 granting Yosemite Valley and the Mariposa Grove of giant sequoias to the State of California "for public use, resort and recreation," the two tracts "shall be inalienable for all time". This is the first instance of park land being set aside specifically for preservation and public use by action of the U.S. federal government, and set a precedent for the 1872 creation of Yellowstone as the first national park.
Simply designating an area a park isn't sufficient to protect it. California did not set up an administration for the park until 1866, when the state appointed Galen Clark as the park's guardian. An 11-year struggle followed to resolve homesteading claims in the valley. The challenge of increasing tourism, with the need to first build stagecoach roads, then the Yosemite Valley Railroad, along with hotels and other facilities in and around the Valley was met during the rest of the 19th century. But much environmental damage was caused to the valley itself at that time.
On October 1, 1890, the U.S. Congress set aside more than 1,500 square miles of “reserved forest lands,” which included areas surrounding the Valley and the Mariposa Grove of Giant Sequoias. In 1906, as a result of the efforts of President Theodore Roosevelt, John Muir, and railroad magnate Edward H. Harriman, Yosemite Valley and the Mariposa Grove were ceded from the State of California’s control and became part of the Yosemite National Park.
As with Yellowstone, the new federal park was under U.S. Army jurisdiction -- Infantry and the Cavalry, also known as “Buffalo Soldiers.” These African American soldiers were charged with protecting the newly formed Yosemite National Park. The cavalry left another legacy in the park, the ranger hat. From 1899 to 1913, the "Buffalo Soldiers" stationed troops at Yosemite and brought with them the trooper's campaign hat with its distinctive Montana Peak we recognize today as the "ranger hat." This peak had been formed into the trooper's stetson by veterans of the 1898 Spanish–American War to better shed tropical rain.
Muir and his Sierra Club continued to lobby the government and influential people for the creation of a unified Yosemite National Park. In May 1903, President Theodore Roosevelt camped with Muir near Glacier Point for three days. On that trip, Muir convinced Roosevelt to take control of Yosemite Valley and Mariposa Grove away from California and return it to the federal government. In 1906, Roosevelt signed a bill that did precisely that. The National Park Service was formed in 1916, and Yosemite was transferred to that agency's jurisdiction.
In the 1920s, nature guides were hired to help educate visitors about the park’s special features; the Field School for Natural History was established to train future interpreters. Today, the National Park Service and volunteers continue to protect Yosemite’s unique natural and cultural treasures.