Atlantic, IA has a population of 6,817 and is the 5,274th largest city in the United States. The population density is 818 per sq mi which is 1398% higher than the Iowa average and 803% higher than the national average. The median age in Atlantic is 44 which is approximately 15% higher than the Iowa average of 38. In Atlantic, 62% of the population over 15 years of age are married, 98% speak English and 2% speak Spanish. 70% of Atlantic residents were born in Iowa, 29% were born out of state, 0% were born outside of the United States and 1% were foreign born.