Hartford, IL has a population of 1,569 and is the 12,437th largest city in the United States. The population density is 336 per sq mi which is 51% higher than the Illinois average and 271% higher than the national average. The median age in Hartford is 36 which is approximately 5% lower than the Illinois average of 37. In Hartford, 54% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 78% of Hartford residents were born in Illinois, 21% were born out of state, 1% were born outside of the United States and 1% were foreign born.