Riverside, ID has a population of 1,114 and is the 14,493rd largest city in the United States. The population density is 519 per sq mi which is 2622% higher than the Idaho average and 473% higher than the national average. The median age in Riverside is 27 which is approximately 25% lower than the Idaho average of 36. In Riverside, 60% of the population over 15 years of age are married, 82% speak English and 18% speak Spanish. 71% of Riverside residents were born in Idaho, 21% were born out of state, 1% were born outside of the United States and 7% were foreign born.