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.