Idaho City, ID has a population of 474 and is the 19,855th largest city in the United States. The population density is 713 per sq mi which is 3636% higher than the Idaho average and 687% higher than the national average. The median age in Idaho City is 34 which is approximately 6% lower than the Idaho average of 36. In Idaho City, 47% of the population over 15 years of age are married, 95% speak English and 4% speak Spanish. 46% of Idaho City residents were born in Idaho, 52% were born out of state, 1% were born outside of the United States and 0% were foreign born.