Hillsborough is an incorporated town in San Mateo County, California, in the San Francisco Bay Area. Hillsborough is one of the wealthiest communities in America and has the highest income of places in the United States with populations of at least 10,000. It is located 17 miles south of San Francisco on the San Francisco Peninsula, bordered by Burlingame to the north, San Mateo to the east, Highlands-Baywood Park to the south, andInterstate 280to the west. The population was 10,825 at the2010 census. The town is served by Hillsborough City School District.
Hillsborough's landscape is dominated by large homes; the town zoning and subdivision ordinances require a 2,500-square-foot minimum house size and minimum lot size of 0.5 acres. As a result, there are no apartments, condominiums or townhouses in the city limits; however, it is not unusual for the homes along the eastern edge of Hillsborough to face condominiums in neighboring Burlingame, sharing the ZIP code 94010. Because lots are large, and with the passage of CA AB 1866 in 2003 which required municipalities to streamline permitting of Alternative Dwelling Units (ADUs, aka "mother-in-law/granny units", "second units", or colloquially "guest houses") and which expanded density bonuses/incentives/credits, Hillsborough residents have added incentive and opportunity to add a second unit, for which the town has issued updated guidelines. This may eventually create a small residential rental market and population, previously almost non-existent for inherent market reasons, due to strong draws of school quality, commuting convenience, and location 'cachet'.

The town has no commercial zoning and thus no businesses within the town limits; the only non-residential properties are the town's 4 public and 3 private schools, town and county government facilities, a golf course, and a small park.

Notable Landmarks:
  • Carolands — Built by Harriet Pullman Carolan, heiress to the Pullman railway. At 65,000 ft², it is one of the largest residences in the United States and is placed on the National Register of Historic Places.
  • ′The Flintstone House′ — designed by architect William Nicholson and built in 1976 using sprayed concrete over balloon-shaped forms, now painted a deep/burnt orange color reminiscent of the Golden Gate Bridge's distinctive hue. The house can be seen to the east from the Doran Memorial Bridge, northbound onHighway 280 between the Bunker Hill and Hayne/Black Mountain exits.
  • Skyfarm — Built by William H. Crocker, namesake of Crocker middle school, and grandson of Charles Crocker of California's Big Four railroad magnates. Designed by Arthur Brown, Jr., and opened in 1930. Home since the 1960s to The Nueva School.
  • Tobin Clark Estate - Originally designed by the noted architect David Adler for Mrs. Celia Tobin Clark, one of the Peninsula’s most prominent families of the early 20th CenturyUplands— Built byTempleton Crocker, as a gift to his fiancéeHelène Irwin, heiress to theC&H Sugar family fortune. Designed by Willis Polk; opened in 1912, with interior of 35,000 ft². Home since the 1950s to Crystal Springs Uplands School.
  • Western White House — Built by William Randolph Hearst and now privately owned. It is structured very similarly to Hearst Castle.
  • Junípero Serra statue — Overlooking Highway 280, the statue was built in honor of Father Junípero Serra.
Notable Residents of Hillsborough:

  • Roxy Bernstein- sports broadcaster
  • Pat Burrell- baseball player
  • Alyssa Campanella- Miss California USA 2011
  • Sam Chavez- professional golfer
  • Jenny Craig- weight loss guru, founder of Jenny Craig, Inc.
  • William H. Crocker- founder and president of Crocker National Bank, chaired Panama-Pacific Exposition Committee and SE Community Chest, member of committee that built San Francisco Opera House and Veterans Building, founder of Crocker Middle School
  • Bing Crosby- singer, actor, raised his second family in Hillsborough
  • Eric Dane- actor
  • Andre Ethier—baseball player
  • Kathy Garver- actress
  • Marjorie Gestring- diver, youngest Olympian to win gold medal
  • Michael Grimes- managing director at Morgan Stanley
  • Patty Hearst- heiress of Hearst newspaper fortuneWilliam Randolph Hearst I- newspaper publisher, politician, builder of Hearst Castle
  • Rickey Henderson- Hall of Fame baseball player
  • Charles Johnson- chairman of Franklin Templeton Investments
  • Brigitte Lin- Taiwanese actress
  • Greg Maddux- Hall of Fame baseball pitcher
  • David Marquardt- co-founder of venture capital firm August Capital
  • Larry Probst- chairman and former CEO of Electronic Arts(EA)
  • Alicia Silverstone- actress
  • J.T. Snow- baseball player
  • Jackie Speier- U.S. Representative from 12th district
  • Lucio Tan- businessman
  • Bud Tribble- vice president of software technology at Apple Inc., among founders ofNeXT, Inc.
  • Troy Tulowitzki- baseball player
  • George Tupou V- King of Tonga
  • Salote Mafile'o Pilolevu Tuita- Tongan princess, only daughter of former KingTāufaʻāhau Tupou IV
  • Siosa'ia Ma'ulupekotofa Tuita- Tongan diplomat and Consul General of San Francisco, husband of Salote Mafile'o Pilolevu Tuita
  • Martin Yan- chef, star of TV show "Yan Can Cook," lives with family in Hillsborough