Carter Lake, IA has a population of 3,765 and is the 7,717th largest city in the United States. The population density is 2,014 per sq mi which is 3587% higher than the Iowa average and 2123% higher than the national average. The median age in Carter Lake is 41 which is approximately 7% higher than the Iowa average of 38. In Carter Lake, 51% of the population over 15 years of age are married, 95% speak English and 4% speak Spanish. 22% of Carter Lake residents were born in Iowa, 75% were born out of state, 1% were born outside of the United States and 2% were foreign born.