South San Francisco is a city located in San Mateo County, California. With a 2020 population of 67,585, it is the 133rd largest city in California and the 555th largest city in the United States. South San Francisco is currently declining at a rate of -0.11% annually but its population has increased by 6.21% since the most recent census, which recorded a population of 63,632 in 2010. South San Francisco reached it's highest population of 67,733 in 2018. Spanning over 30 miles, South San Francisco has a population density of 7,326 people per square mile.
The average household income in South San Francisco is $120,721 with a poverty rate of 7.52%. The median rental costs in recent years comes to $1,888 per month, and the median house value is $784,800. The median age in South San Francisco is 40 years, 38.8 years for males, and 41 years for females. For every 100 females there are 96.3 males.