Greenfield, IL has a population of 1,317 and is the 13,479th largest city in the United States. The population density is 768 per sq mi which is 246% higher than the Illinois average and 748% higher than the national average. The median age in Greenfield is 36 which is approximately 5% lower than the Illinois average of 37. In Greenfield, 56% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 91% of Greenfield residents were born in Illinois, 9% were born out of state, 0% were born outside of the United States and 0% were foreign born.