Harmon, IL has a population of 151 and is the 25,633rd largest city in the United States. The population density is 1,036 per sq mi which is 366% higher than the Illinois average and 1043% higher than the national average. The median age in Harmon is 40 which is approximately 7% higher than the Illinois average of 37. In Harmon, 52% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 91% of Harmon residents were born in Illinois, 9% were born out of state, 0% were born outside of the United States and 0% were foreign born.