Hartley, IA has a population of 1,717 and is the 11,928th largest city in the United States. The population density is 1,323 per sq mi which is 2322% higher than the Iowa average and 1360% higher than the national average. The median age in Hartley is 44 which is approximately 17% higher than the Iowa average of 38. In Hartley, 69% of the population over 15 years of age are married, 96% speak English and 3% speak Spanish. 79% of Hartley residents were born in Iowa, 18% were born out of state, 1% were born outside of the United States and 3% were foreign born.