Riverdale Park, CA has a population of 1,056 and is the 14,810th largest city in the United States. The population density is 726 per sq mi which is 213% higher than the California average and 702% higher than the national average. The median age in Riverdale Park is 29 which is approximately 20% lower than the California average of 36. In Riverdale Park, 31% of the population over 15 years of age are married, 45% speak English and 47% speak Spanish. 58% of Riverdale Park residents were born in California, 13% were born out of state, 0% were born outside of the United States and 28% were foreign born.