Riverdale, GA has a population of 15,812 and is the 2,706th largest city in the United States. The population density is 3,585 per sq mi which is 2048% higher than the Georgia average and 3857% higher than the national average. The median age in Riverdale is 33 which is approximately 10% lower than the Georgia average of 36. In Riverdale, 36% of the population over 15 years of age are married, 85% speak English and 6% speak Spanish. 48% of Riverdale residents were born in Georgia, 39% were born out of state, 1% were born outside of the United States and 12% were foreign born.