Sergeant Bluff, IA has a population of 4,399 and is the 7,011th largest city in the United States. The population density is 1,504 per sq mi which is 2653% higher than the Iowa average and 1560% higher than the national average. The median age in Sergeant Bluff is 33 which is approximately 14% lower than the Iowa average of 38. In Sergeant Bluff, 67% of the population over 15 years of age are married, 97% speak English and 0% speak Spanish. 65% of Sergeant Bluff residents were born in Iowa, 32% were born out of state, 2% were born outside of the United States and 1% were foreign born.