Armington, IL has a population of 363 and is the 21,414th largest city in the United States. The population density is 1,273 per sq mi which is 473% higher than the Illinois average and 1305% higher than the national average. The median age in Armington is 31 which is approximately 18% lower than the Illinois average of 37. In Armington, 67% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 77% of Armington residents were born in Illinois, 21% were born out of state, 2% were born outside of the United States and 0% were foreign born.