San Gabriel, CA has a population of 40,200 and is the 1,031st largest city in the United States. The population density is 9,699 per sq mi which is 4074% higher than the California average and 10606% higher than the national average. The median age in San Gabriel is 42 which is approximately 17% higher than the California average of 36. In San Gabriel, 57% of the population over 15 years of age are married, 27% speak English and 17% speak Spanish. 39% of San Gabriel residents were born in California, 5% were born out of state, 1% were born outside of the United States and 56% were foreign born.