is an incorporated town in San Mateo County, California, United States. The population was 4,462 at the 2000 census. It was named for Spanish explorer Gaspar de Portola, who led the first party of Europeans to explore the San Francisco Peninsula, in 1769.
Portola Valley is one of the top 20 wealthiest towns in the United States of America, with a median household income of $200,000+ a year. In
magazine's list of most expensive homes by ZIP code, it ranked 21st in 2005, with a median price of $1,600,000.
Portola Valley is located at (37.375023, -122.218635), on the eastern slope of the Peninsula Coastal Range of the Santa Cruz Mountains. The Windy Hill Open Space Preserve is on the town's southwest side and the Jasper Ridge Biological Preserve is on the north side of town. It is off Interstate 280, near Woodside, just west of Palo Alto and Los Altos and south of Menlo Park, and is in a mostly wooded area, with some open plains.
According to the United States Census Bureau, the town has a total area of 9.2 square miles (23.7 km²), all land.