Gustine, CA has a population of 5,684 and is the 5,956th largest city in the United States. The population density is 3,665 per sq mi which is 1477% higher than the California average and 3945% higher than the national average. The median age in Gustine is 38 which is approximately 6% higher than the California average of 36. In Gustine, 54% of the population over 15 years of age are married, 48% speak English and 48% speak Spanish. 58% of Gustine residents were born in California, 10% were born out of state, 0% were born outside of the United States and 32% were foreign born.