The population was 11, at the census. Howard settled his family in this area, which attracted wealthy San Franciscans. On May 5, , Hillsborough residents voted to incorporate. In , Jack and Betty Ken, the first-generation children of Chinese Immigrants, purchased land in the town.
This made them the first non-white people to own land in the town, effectively desegregating Hillsborough. According to the United States Census Bureau , the town has a total area of 6. The area's considerably winding, hilly topography , 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 freeway to El Camino Real and the towns of Burlingame and San Mateo.
In all 3 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.
Commonly observed mammals include California mule deer , raccoons , opossum , coyotes, rabbits, squirrels, and skunks. Mountain lions are known to live and roam in the green belts that surround the city. Hillsborough is bordered by Burlingame to the north, San Mateo to the east, Highlands-Baywood Park to the south, and Interstate to the west. Hillsborough's landscape is dominated by large homes; the town zoning and subdivision ordinances require a 2,square-foot m 2 minimum house size and minimum lot size of 0.
The town has no commercial zoning and thus no businesses within the town limits; the only non-residential properties are the town's four public and three private schools, town and county government facilities, a golf course, a country club, and small parks.
