Carroll, IA has a population of 9,990 and is the 3,943rd largest city in the United States. The population density is 1,743 per sq mi which is 2959% higher than the Iowa average and 1824% higher than the national average. The median age in Carroll is 41 which is approximately 9% higher than the Iowa average of 38. In Carroll, 62% of the population over 15 years of age are married, 98% speak English and 2% speak Spanish. 82% of Carroll residents were born in Iowa, 16% were born out of state, 0% were born outside of the United States and 1% were foreign born.