Foster City is an affluent planned city located in San Mateo County, California, 94404. As of the 2010 census, the city had a total population of 30,567. Forbes ranked Foster City #10 on their 2009 list of America's Top 25 Towns to Live Well. Money has also recognized Foster City multiple times as one of the Best Places to Live. Foster City is sometimes considered to be part of Silicon Valley for its local industry and its proximity to Silicon Valley cities.