New Milford, IL has a population of 644 and is the 17,984th largest city in the United States. The population density is 447 per sq mi which is 101% higher than the Illinois average and 394% higher than the national average. The median age in New Milford is 48 which is approximately 28% higher than the Illinois average of 37. In New Milford, 63% of the population over 15 years of age are married, 86% speak English and 8% speak Spanish. 71% of New Milford residents were born in Illinois, 22% were born out of state, 0% were born outside of the United States and 7% were foreign born.