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 (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 11,273 as of 2013. 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 (230 m2) minimum house size and minimum lot size of 0.5 acres (2,000 m2).[5] 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.

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 a small park.