Sully, IA has a population of 843 and is the 16,244th largest city in the United States. The population density is 1,440 per sq mi which is 2536% higher than the Iowa average and 1490% higher than the national average. The median age in Sully is 41 which is approximately 7% higher than the Iowa average of 38. In Sully, 72% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 88% of Sully residents were born in Iowa, 11% were born out of state, 1% were born outside of the United States and 0% were foreign born.