Foster City is a city located in San Mateo County, California. The 2020 census put the population at 33,805, an addition of higher than 10% over the 2010 census figure of 30,567. Foster City is sometimes considered to be allocation of Silicon Valley for its local industry and its proximity to Silicon Valley cities. Foster City is one of the United States’ safest cities, with an average of one murder per decade.

Foster City was founded in the 1960s, built upon the existing Brewer Island in the marshes of the San Francisco Bay on the east edge of San Mateo, enlarged past engineered landfill. The city was named after T. Jack Foster, a real estate magnate who owned much of the house comprising the city and who was instrumental in its initial design. His firm, Foster Enterprises, now tell his descendants, relocated to San Mateo in 2000 and is nevertheless active in genuine estate affairs throughout the San Francisco Bay Area.

According to the United States Census Bureau, the city has a total Place of 19.8 square miles (51 km), of which 3.8 square miles (9.8 km²) is estate and 16.1 square miles (42 km) is water. The total area is 81.07% water. Foster City has ongoing issues afterward water intrusion from the San Francisco Bay and is potentially subject to remaining inundation as the sea level rises. A project to add up the existing levee behind a steel-reinforced wall has been underway previously FEMA designated the entire area as a floodplain making residents subject to much far along flood insurance rates.

Foster City, like most of the peninsula, has a smooth Mediterranean climate, with warm, dry summers and cool, wet winters. The warmest month of the year is September, with an average daytime temperature of 77.8 °F (25.4 °C) and an average nighttime temperature of 53.8 °F (12.1 °C), while the coldest month of the year is January, with an average daytime temperature of 58 °F (14 °C) and an average nighttime temperature of 41.5 °F (5.3 °C).