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Hillsborough, California
Town of Hillsborough
Official seal of Hillsborough, California
Location of Hillsborough in San Mateo County, California.
Location of Hillsborough in San Mateo County, California.
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Country United States
State California
County San Mateo
Incorporated May 5, 1910
 • Total 6.17 sq mi (15.97 km2)
 • Land 6.17 sq mi (15.97 km2)
 • Water 0.00 sq mi (0.00 km2)  0%
322 ft (98 m)
 • Total 11,387
 • Density 1,847.1/sq mi (713.15/km2)
Time zone UTC-8 (Pacific)
 • Summer (DST) UTC-7 (PDT)
ZIP code
Area code 650
FIPS code 06-33798
GNIS feature IDs 1659735, 2412752

Hillsborough is an incorporated town in San Mateo County, California, in the San Francisco Bay Area. It is located 17 miles (27 km) 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, and Interstate 280 to the west. The population was 11,387 as of 2020.


Hillsborough is located on the Rancho San Mateo Mexican land grant which was purchased by William Davis Merry Howard, son of a wealthy Hillsborough, New Hampshire, shipping magnate, in 1846. Howard settled his family in this area, which attracted wealthy San Franciscans. Hillsborough is near Burlingame. In 1910, Hillsborough residents voted to incorporate.

Geography and environment

Hillsborough is located at 37°33′37″N 122°21′23″W / 37.560199°N 122.356277°W / 37.560199; -122.356277.

According to the United States Census Bureau, the town has a total area of 6.2 square miles (16 km2), all of it land. The area's considerably winding, hilly topography (unsurprising given the town's name), and impossibility of a grid layout, make Hillsborough notoriously challenging to navigate. Many lots include fairly steep slopes, particularly the western side of the town, with the landscape generally flattening to the east as it descends from the 280 freeway to El Camino Real and the towns of Burlingame and San Mateo.

Two prominent streams drain the mostly wooded slopes of Hillsborough: San Mateo Creek and Cherry Creek. In both cases the upper watersheds are closed-canopy California oak woodlands, with dominant trees of Coast Live Oak, Pacific Madrone and California Bay.

The upper drainage area of San Mateo Creek in Hillsborough contains significant serpentinite outcrops, which are known habitats for several rare plant species including the San Mateo woolly sunflower. Other common plants include toyon, gooseberry, lupine, monkeyflower and coffeeberry. Commonly observed mammals include California mule deer, raccoons, opossum, coyotes, rabbits, squirrels, and skunks.

Hillsborough is bordered by Burlingame to the north, San Mateo to the east, Highlands-Baywood Park to the south, and Interstate 280 to the west.


Historical population
Census Pop.
1920 931
1930 1,891 103.1%
1940 2,747 45.3%
1950 3,552 29.3%
1960 7,554 112.7%
1970 8,753 15.9%
1980 10,372 18.5%
1990 10,667 2.8%
2000 10,825 1.5%
2010 10,825 0.0%
2020 11,387 5.2%
U.S. Decennial Census


At the 2010 census Hillsborough had a population of 10,825. The population density was 1,748.9 people per square mile (675.3/km2). The racial makeup of Hillsborough was 7,178 (66.3%) White, 42 (0.4%) African American, 7 (0.1%) Native American, 3,044 (28.1%) Asian, 23 (0.2%) Pacific Islander, 109 (1.0%) from other races, and 422 (3.9%) from two or more races. Hispanic or Latino of any race were 373 people (3.4%).

The census reported that 10,825 people (100% of the population) lived in households, as no other type of residence exists in Hillsborough.

There were 3,693 households, 1,445 (39.1%) had children under the age of 18 living in them, 2,804 (75.9%) were opposite-sex married couples living together, 220 (6.0%) had a female householder with no husband present, 114 (3.1%) had a male householder with no wife present. There were 66 (1.8%) unmarried opposite-sex partnerships, and 34 (0.9%) same-sex married couples or partnerships. 451 households (12.2%) were one person and 309 (8.4%) had someone living alone who was 65 or older. The average household size was 2.93. There were 3,138 families (85.0% of households); the average family size was 3.18.

The age distribution was 2,877 people (26.6%) under the age of 18, 466 people (4.3%) aged 18 to 24, 1,600 people (14.8%) aged 25 to 44, 3,667 people (33.9%) aged 45 to 64, and 2,215 people (20.5%) who were 65 or older. The median age was 47.5 years. For every 100 females, there were 94.8 males. For every 100 females age 18 and over, there were 91.9 males.

There were 3,912 housing units at an average density of 632.0 per square mile, of the occupied units 3,490 (94.5%) were owner-occupied and 203 (5.5%) were rented. The homeowner vacancy rate was 1.3%; the rental vacancy rate was 4.2%. 10,206 people (94.3% of the population) lived in owner-occupied housing units and 619 people (5.7%) lived in rental housing units.

In 2019, a Bloomberg analysis ranked Hillsborough as the fifth richest town in the United States.


At the 2000 census there were 10,825 people, 3,689 households, and 3,161 families in the town. The population density was 1,738.7 people per square mile (670.9/km2). There were 3,804 housing units at an average density of 611.0 per square mile (235.8/km2). Of the 3,689 households 36.3% had children under the age of 18 living with them, 78.6% were married couples living together, 4.9% had a female householder with no husband present, and 14.3% were non-families. 11.1% of households were one person and 7.3% were one person aged 65 or older. The average household size was 2.93 and the average family size was 3.14.

The age distribution was 25.1% under the age of 18, 4.4% from 18 to 24, 19.7% from 25 to 44, 32.2% from 45 to 64, and 18.6% 65 or older. The median age was 46 years. For every 100 females, there were 94.6 males. For every 100 females age 18 and over, there were 91.6 males.

The median household income was $193,157 and the median family income was $200,000. Full-time male workers have a median income of $100,000+ versus $55,882 for full-time female workers. The per capita income for the town was $98,643. About 1.8% of families and 2.8% of the population were below the poverty line, including 2.7% of those under age 18 and 0.8% of those age 65 or over. According to The Best Places to Live 2007 in Money Magazine, Hillsborough's $263,456 median household income is the highest in the country.


Primarily a residential suburb of San Francisco, Hillsborough has many mansions and other points of interest within the town's borders dating from the early 20th century.

  • Carolands — Built by Harriet Pullman Carolan, heiress to the Pullman railway. At 65,000 ft² (6,000 m²), it is one of the largest residences in the United States and is placed on the National Register of Historic Places.
  • ′The Flintstone House′ (a.k.a. the Adobe/Dome/Bubble/Marshmallow/Gumby 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 on Highway 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 Century
  • Uplands — Built by Templeton Crocker, as a gift to his fiancée Helène Irwin, heiress to the C&H Sugar family fortune. Designed by Willis Polk; opened in 1912, with interior of 35,000 ft² (3,250 m²). Home since the 1950s to Crystal Springs Uplands School.
  • Western White House — Commissioned by George Randolph Hearst, son of William Randolph Hearst and now privately owned. It, like Hearst Castle was designed by Julia Morgan.
  • Junípero Serra statue — Overlooking Highway 280, the statue was built in honor of Father Junípero Serra.


December is the coolest month with an average high of 60 degrees, and September is the warmest month with an average high of 78 degrees. Hillsborough has a Mediterranean climate (Köppen climate classification Csa), with the vast majority of the precipitation from the months of November to April. On average, Hillsborough receives 17 inches (430 mm) of rain. With coastal mountains to the west of Hillsborough, it is blocked in the winter from much of the rainfall over Half Moon Bay, and in the summer it is blocked from virtually all the fog of the coast. Hillsborough receives an average of 307 days of sunshine annually, with 52 days of recordable precipitation per year.

Notable people

  • Toni Breidinger – NASCAR Driver
  • Roxy Bernstein – sports broadcaster
  • Pat Burrell – baseball player
  • Alyssa Campanella – Miss California USA 2011
  • Sam Chavez – professional golfer
  • Imelda Marcos - former first lady of the Philippines
  • Jenny Craig – weight loss guru, founder of Jenny Craig, Inc.
  • William H. Crocker – founder and president of Crocker National Bank, member of committee that built San Francisco Opera House and Veterans Building
  • Bing Crosby – singer, actor, raised his second family in Hillsborough
  • Nathaniel Crosby – U.S. Amateur golf champion, son of Bing Crosby
  • 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 fortune
  • William Randolph Hearst I – newspaper publisher, politician, builder of Hearst Castle
  • Rickey Henderson – Hall of Fame baseball player
  • Charles B. Johnson – former chairman at Franklin Templeton Investments
  • Brigitte Lin – Taiwanese actress
  • Phyllis Welch MacDonald - actress
  • Greg Maddux – Hall of Fame baseball pitcher
  • David Marquardt – co-founder of venture capital firm August Capital
  • Timothy Francis McCarthy – Former President of Charles Schwab
  • Larry Probst – chairman and former CEO of Electronic Arts (EA)
  • Alicia Silverstone - grew up in Hillsborough actress
  • J.T. Snow – baseball player
  • Jackie Speier – U.S. Representative from 14th district
  • Ryan Roslansky - CEO of LinkedIn
  • Lucio Tan – businessman
  • Bud Tribble – vice president of software technology at Apple Inc., among founders of NeXT, Inc.
  • Marshall Tuck – politician
  • Troy Tulowitzki – baseball player
  • George Tupou V – King of Tonga
  • Salote Mafile'o Pilolevu Tuita – Tongan princess, only daughter of former King Tāufaʻāhau 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
  • Jimmy Kimmel – Comedian
  • Jeremy Lin - Professional basketball player
  • Alden W. Clausen - President, The World Bank (1981-1986), President & CEO BankAmerica Corp. & Bank of America NT&SA (1970-1981 & 1986-1991)
  • Caspar Weinberger - Secretary of Defense, Secretary of Health, Education & Welfare

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