California’s landforms are the Sierra Nevada, the Central Valley, the Coast Ranges, the volcanic peaks of the southern Cascades, and the basins and ranges of the Mojave and Great Basin deserts, all packed into 423,970 km² (163,696 sq mi), the third-largest area of any US state. The state holds both extremes of the lower 48: Mount Whitney, the highest point in the contiguous United States at 4,421 m (14,505 ft), and Badwater Basin in Death Valley, the lowest point in North America at 86 m (282 ft) below sea level. The two sit only about 137 km (85 mi) apart, the greatest elevation gradient in the contiguous United States. Six named places explain how the rest of the state was built.
Mount Whitney and the Sierra Nevada’s Eastern Wall
Mount Whitney stands on the Sierra Crest at the boundary of Inyo and Tulare counties, and its two sides tell the story of the whole range. From the west it rises gently, only about 914 m (3,000 ft) above the John Muir Trail at Guitar Lake. From the east it towers 3,285 m (10,778 ft) above the town of Lone Pine in the Owens Valley, just 24 km (15 mi) away. That lopsided shape is the signature of a tilted fault block: the Sierra Nevada is anchored in the west and has been rising along a fault system at its eastern base, while the Owens Valley has dropped. The same stretching of the crust built the Basin and Range country that fills Nevada next door.
The rock is granite of the Sierra Nevada Batholith, masses of magma that rose during the Cretaceous and cooled underground. In the last 2 to 10 million years the range was pushed up far enough for rivers and glaciers to strip off the softer rock above and expose it. Water from Whitney splits between two worlds: the west slope drains to the Kern River and the Tulare Basin, while the east side feeds Lone Pine Creek, most of which is diverted into the Los Angeles Aqueduct.
The peak was named in July 1864 by the California Geological Survey after Josiah Whitney, the state geologist. Three men from Lone Pine, Charles Begole, A. H. Johnson and John Lucas, made the first ascent on August 18, 1873, while on a fishing trip. Further north the same fault-block pattern created the basin that holds Lake Tahoe, which straddles the Nevada border at 1,897 m (6,225 ft), plunges to 501 m (1,645 ft) deep, and is the largest alpine lake in North America.
Badwater Basin, 86 Metres Below the Sea
Death Valley runs north to south between the Amargosa Range on the east and the Panamint Range on the west, covering about 7,800 km² (3,000 sq mi), mostly in Inyo County. Geologists call it a graben, a block of crust that has dropped between two mountain fronts. Telescope Peak in the Panamint Range reaches 3,368 m (11,049 ft), and its summit stands 3,454 m above Badwater in a horizontal distance of about 24 km (15 mi). The valley is also cut by the Death Valley and Furnace Creek faults, and the eastern end of the Garlock Fault meets the Death Valley Fault.
Badwater itself is a small spring-fed pool beside the road. Salts from the surrounding basin make the water undrinkable, which gave the place its name. The true lowest point, only slightly deeper, lies several miles to the west and moves with rain and evaporation; because the salt crust is often a thin skin over mud, the low-point sign stands at the pool instead. During wetter phases of the Pleistocene the valley held Lake Manly, nearly 160 km (100 mi) long and 180 m (600 ft) deep, the last basin in a chain of lakes that began at Mono Lake. When it dried, it left a salt crust between 8 and 152 cm thick, about 95 percent table salt. The biggest salt pan in the national park stretches 64 km (40 mi) and covers roughly 520 km² (200 sq mi) of the valley floor.
The depth of the trough also explains its heat. Pacific air loses its moisture over four mountain ranges, the Sierra Nevada and the Panamint Range among them, before it arrives, so the basin averages about 48 mm (1.9 in) of rain against an evaporation potential of about 3,800 mm (150 in) a year. On July 10, 1913, the Weather Bureau recorded 56.7°C (134°F) at Furnace Creek, still listed as the world’s highest air temperature, although some modern experts dispute it. Readings of 54.4°C (130°F) in August 2020 and July 2021 are the highest considered fully reliable. More on the park’s salt pans, dunes and canyons is in our Death Valley National Park guide.
Yosemite Valley and the Granite Walls of the Merced River
Yosemite Valley lies on the western slope of the Sierra Nevada, about 240 km (150 mi) east of San Francisco. It is roughly 12 km (7.5 mi) long and 1.6 km (1 mi) wide, with a flat floor at about 1,200 m (4,000 ft) and granite cliffs rising 910 to 1,070 m (3,000 to 3,500 ft) above it. Streams first deepened the valley and exposed the granite; repeated glaciations then excavated the bedrock floor, and sediment from Ancient Lake Yosemite, dammed by a moraine near El Capitan, left the floor flat. More than half a dozen creeks now tumble into it from hanging valleys.
Most visitors enter from the west at Tunnel View, where the first features are El Capitan on the left and Cathedral Rocks with Bridalveil Fall on the right. Further in come Sentinel Rock, the Three Brothers, the Royal Arches and Glacier Point, which stands 992 m (3,254 ft) above the valley floor. At the eastern end is Half Dome, a body of quartz monzonite that solidified deep underground and was exposed by erosion. Seen from the valley it looks like a dome sliced in two, but from Washburn Point it is revealed as a thin ridge, or arête. Yosemite Falls drops 739 m (2,425 ft) in three sections and is the highest waterfall in North America. Upstream on the Merced, Nevada Fall (181 m) and Vernal Fall (97 m) form what is called the Giant Staircase.
Above the eastern end, Clouds Rest reaches 3,025 m (9,924 ft), the highest point near the valley. The wider range, from Lake Tahoe southward, is covered in our Sierra Nevada mountain range guide.
The Central Valley, 720 Kilometres of Flat Land
Over millennia, sediment from the Coast Ranges and the rising Sierra Nevada filled the Central Valley until its floor lay almost flat and barely above sea level. The trough is about 720 km (450 mi) long and 60 to 100 km (40 to 60 mi) wide, covering about 47,000 km² (18,000 sq mi), about 11 percent of California’s land. Its older name, the Great Valley, survives in scientific use, notably in the Great Valley Sequence of rocks.
The valley has three parts. The Sacramento Valley in the north gets more than 510 mm (20 in) of rain a year. The San Joaquin Valley to the south is drier, and the Tulare Basin at the southern end is semi-arid and drains inward, its water essentially never reaching the ocean. The Sacramento and San Joaquin rivers meet in the Sacramento–San Joaquin Delta, a maze of channels, sloughs and peat islands that empties through Suisun and San Pablo bays into San Francisco Bay and out the Golden Gate. More than 28,000 km² (7 million acres) of the valley are irrigated by reservoirs and canals, and on less than 1 percent of US farmland the valley produced 8 percent of the nation’s agricultural output by value, US$43.5 billion in 2013. About 7.2 million people lived there in 2020, in cities spaced along its length: Redding, Sacramento, Fresno and Bakersfield. Our Central Valley guide follows the valley county by county.
Mount Shasta, Where the Cascades Begin
At the northern end of the Central Valley the land changes character completely. Mount Shasta, in Siskiyou County, is a potentially active stratovolcano at the southern end of the Cascade Range, the chain of volcanoes that runs north through Oregon and Washington. It reaches 4,322 m (14,179 ft), making it the second-highest peak in the Cascades and the fifth-highest in California, and it rises almost 3,000 m above the surrounding country. With an estimated volume of 350 km³ (85 cubic miles), it is the most voluminous stratovolcano in the Cascade Volcanic Arc. On a clear winter day it can be seen from the floor of the Central Valley 230 km (140 mi) to the south.
Shasta is built from four overlapping cones, including the satellite cone Shastina at 3,760 m (12,330 ft). Seven named glaciers cling to it; the Whitney Glacier is the longest and the Hotlum Glacier is the most voluminous in California. The mountain has long been a landmark on the Siskiyou Trail, the old footpath route between the Central Valley and the Pacific Northwest that the Central Pacific Railroad followed when it was completed in 1887.
The Carrizo Plain and the San Andreas Fault
California’s landforms exist because the state straddles the boundary between the Pacific and North American plates. The San Andreas Fault runs roughly 1,210 km (750 mi) through the state, from the Mendocino triple junction near Eureka to the Salton Sea, and its average slip rate is 20 to 35 mm a year. On the Carrizo Plain in San Luis Obispo County it lies open.
The plain is an enclosed grassland about 80 km (50 mi) long and up to 24 km (15 mi) wide, at an average of about 670 m (2,200 ft), held between the Temblor Range to the northeast and the Caliente Range to the southwest. Caliente Mountain, at 1,556 m (5,106 ft), is the highest point in the county. The plain drains inward to Soda Lake, a 12 km² alkali lake with no outlet. Along the foot of the Temblor Range the fault shows as a line of offset ridges and gullies, clearest in early morning or evening light.
Wallace Creek is the textbook example. The small stream crosses the fault at a right angle, and its bed has been dragged sideways by about 130 m (425 ft) over roughly the past 3,700 years. About 7 m of that shift happened in a single event, the Fort Tejon earthquake of 1857. Measurements at Wallace Creek by the geologists Sieh and Jahns produced the first slip rate ever determined for the San Andreas. If you want to follow the fault beyond the Carrizo Plain, our San Andreas Fault guide covers the plate boundary that runs beneath so many of these California landforms.