Home to Silicon Valley, Santa Clara County is an economic center for high technology, and had the third-highest gross domestic product (GDP) per capita in the world as of 2015 behind Zürich and Oslo, according to the Brookings Institution.

In the early 20th century, the area was promoted as the "Valley of the Heart's Delight" due to its natural beauty, including a significant number of orchards.

[14] The region was also memorably referred to as the "sun-kissed Santa Clara Valley" in Jack London's 1903 Call of the Wild.

Both tule elk (Cervus canadensis nannodes) and pronghorn (Antilocapra americana) were historically native to Santa Clara County.

In June 1776, Lieutenant Commander Don José Joaquín Moraga led a group of soldiers and colonists from the Presidio of Monterey to establish Mission San Francisco de Asis and encountered both tule elk and pronghorn, and clearly distinguished these two species from deer.

Regarding elk, Moraga wrote: "In the great plain called San Bernardino (the Santa Clara Valley which stretches from south San Jose to Gilroy), while the expedition was strung out at length, we descried in the distance a herd of large animals that looked like cattle, but we could not imagine where they belonged or from whence they had come...with horns similar in shape to those of the deer, but so large that they measured sixteen palms from tip to tip."

"[17] Regarding pronghorn, Moraga reported: "In the said plains of San Bernardino (Santa Clara Valley)…there is another species of deer about the size of three-year-old sheep.

"[17] Herbert Eugene Bolton also wrote of elk reports from another Spanish expedition, from the De Anza Expedition on March 23, 1776: " In Gilroy Valley (Santa Clara Valley) Moraga 's larder was replenished by three elks which the men killed without leaving the road.

"[18] General John Bidwell, of the 1841 Bartleson-Bidwell Party wrote: "In some of the fertile valleys, such as Napa and Santa Clara, there were elk literally by the thousand.

While other ranchers refused, tech pioneers Bill Hewlett and David Packard allowed Coletto and state biologists to translocate the initial 32 tule elk from the Owens Valley in the eastern Sierra onto the 28,000-acre (11,000 ha) San Felipe Ranch, which the families jointly own, in the hills east of Morgan Hill.

[20] From the three original 1978–1981 translocations (totaling 65 animals) to the Mount Hamilton region of the Diablo Range, there are multiple herds in different locations including the Isabel Valley, San Antonio Valley, Livermore area, San Felipe Ranch, Metcalf Canyon, Coyote Ridge, Anderson Lake, and surrounding areas such as the Sunol and Cottonwood Creek (near San Luis Reservoir in western Merced County, California) herds.

[23] As of 2017 there were four herds in the Coyote Ridge area, often visible from U. S. Highway 101, according to Craige Edgerton, recently retired executive director of the Silicon Valley Land Conservancy and local naturalist Michael Hundt.

[25] The elk herds in eastern Santa Clara County are blocked from dispersal to the west by U.S. Highway 101, with environmentalists advocating re-purposing the Metcalf Road bridge at the Coyote Gap into a wildlife overcrossing.

In 1990, the California Department of Fish and Game's Henry Coletto translocated excess pronghorn from Modoc County to six locations in California, including 51 animals to the San Felipe Ranch in Santa Clara County, where the swift-footed ungulates had not lived for generations.

[26] The animals left the San Felipe Ranch for the Isabel and San Antonio Valleys, as well as an area near Lake Del Valle in Alameda County may now be extirpated by poaching, highway vehicle collisions, and insufficient numbers to defend pronghorn fawns against coyote predation.

Acquisitions to date include the 1,756-acre (711 ha) Rancho Cañada de Pala, straddling the Alameda Creek and Coyote Creek watersheds for California tiger salamander habitat; a conservation easement on the 3,259-acre Blue Oak Ranch Reserve, which abuts the north side of Joseph D. Grant County Park; a conservation easement on the 28,359-acre San Felipe Ranch, connecting Joseph D. Grant County Park with Henry W. Coe State Park; the 2,899-acre South Valley Ranch which protects a tule elk herd in the San Antonio Valley, and other properties.

[34] The vast majority of these Superfund sites were caused by firms associated with the high tech sector in Silicon Valley.

[35] Census demographics data released in 2019 show Asian Americans have had the plurality of Santa Clara's population since 2014.

From 1872 through 1984, the only Democrats to carry Santa Clara County were Franklin Roosevelt, Lyndon Johnson, and Hubert Humphrey.

However, 1988 would begin to mark a significant shift in the county's political leanings, starting with Michael Dukakis' narrow win and culminating in Bill Clinton's substantial 20-point victory in 1992.

[62] In November 2012, all of the cities, towns, and unincorporated areas of Santa Clara County had more registered Democrats than Republicans.

Technology, both hardware and software, dominates the service sector by value, but like any other county, Santa Clara has its share of retail and office support workers.

The San Jose/Sunnyvale/Santa Clara metropolitan region, comprising Santa Clara County and San Benito County, was ranked as the highest performing metropolitan area in the US in 2012, ahead of Austin, Texas and Raleigh, North Carolina, according to the Milken Institute.

[73] School districts include:[74] Santa Clara County Library is a public library system serving the communities and cities of Campbell, Cupertino, Gilroy, Los Altos, Los Altos Hills, Milpitas, Monte Sereno, Morgan Hill, Saratoga, and all unincorporated areas of the county.

San Francisco International Airport (SFO) is also often used for commercial services by residents of Santa Clara County.

The Santa Clara Valley Transportation Authority operates the VTA light rail system, which primarily serves San Jose, with one line continuing as far north as Mountain View.

Expressways in California are distinct from freeways; although access to adjoining properties is eliminated, at-grade intersections are allowed.