Riverside, IA has a population of 1,054 and is the 14,822nd largest city in the United States. The population density is 597 per sq mi which is 993% higher than the Iowa average and 559% higher than the national average. The median age in Riverside is 42 which is approximately 11% higher than the Iowa average of 38. In Riverside, 60% of the population over 15 years of age are married, 97% speak English and 0% speak Spanish. 72% of Riverside residents were born in Iowa, 24% were born out of state, 2% were born outside of the United States and 3% were foreign born.