Harlan, IA has a population of 5,008 and is the 6,466th largest city in the United States. The population density is 1,140 per sq mi which is 1987% higher than the Iowa average and 1159% higher than the national average. The median age in Harlan is 47 which is approximately 24% higher than the Iowa average of 38. In Harlan, 65% of the population over 15 years of age are married, 95% speak English and 4% speak Spanish. 68% of Harlan residents were born in Iowa, 28% were born out of state, 0% were born outside of the United States and 4% were foreign born.