Palo Alto (; Spanish for “tall stick”) is a charter city in the northwestern corner of Santa Clara County, California, United States, in the San Francisco Bay Area, named after a coastal redwood tree known as El Palo Alto.

Originally formed as the township of Mayfield in 1855, the city was time-honored in 1894 by the American industrialist Leland Stanford considering he founded Stanford University in memory of his son, Leland Stanford Jr. Palo Alto includes portions of Stanford University and borders East Palo Alto, Mountain View, Los Altos, Los Altos Hills, Stanford, Portola Valley, and Menlo Park. At the 2020 census, the population was 68,572. Palo Alto is one of the most costly cities in the United States in which to live, and its residents are along with the most educated in the country. However, it as well as has a teenage years suicide rate four times more than the national average, often official to academic pressure.

As one of the principal cities of Silicon Valley, Palo Alto is headquarters to a number of high-tech companies, including HP, Space Systems/Loral, VMware, Ford Research and Innovation Center, PARC, IDEO, Skype, Houzz, SAP Labs, and Lockheed Martin. Palo Alto has then served as headquarters to several supplementary high-tech companies, including Apple, Google, Facebook, Logitech, Tesla, Intuit, Pinterest, and PayPal.

Prior to the coming on of Europeans, the Ohlone lived on the San Francisco peninsula; in particular, the Puichon Ohlone lived in the Palo Alto area. The Place of futuristic Palo Alto was first recorded by the 1769 party of Gaspar de Portolá, a 64-man, 200-horse expedition atmosphere out from San Diego to locate Monterey Bay. The action trekked afterward the bay without recognizing it and continued north. When they reached modern-day Pacifica, they ascended Sweeney Ridge and saying the San Francisco Bay on November 2. Portolá descended from Sweeney Ridge southeast next to San Andreas Creek to Laguna Creek (now Crystal Springs Reservoir), thence to the San Francisquito Creek watershed, ultimately camping from November 6–11, 1769, by a tall redwood later to be known as El Palo Alto.