Greenfield, IA has a population of 1,951 and is the 11,170th largest city in the United States. The population density is 1,076 per sq mi which is 1869% higher than the Iowa average and 1087% higher than the national average. The median age in Greenfield is 46 which is approximately 20% higher than the Iowa average of 38. In Greenfield, 65% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 86% of Greenfield residents were born in Iowa, 12% were born out of state, 0% were born outside of the United States and 1% were foreign born.