San Joaquin, CA has a population of 4,011 and is the 7,442nd largest city in the United States. The population density is 3,350 per sq mi which is 1341% higher than the California average and 3597% higher than the national average. The median age in San Joaquin is 25 which is approximately 32% lower than the California average of 36. In San Joaquin, 57% of the population over 15 years of age are married, 10% speak English and 87% speak Spanish. 48% of San Joaquin residents were born in California, 3% were born out of state, 1% were born outside of the United States and 47% were foreign born.