Hamilton, IL has a population of 2,916 and is the 8,950th largest city in the United States. The population density is 819 per sq mi which is 268% higher than the Illinois average and 804% higher than the national average. The median age in Hamilton is 44 which is approximately 17% higher than the Illinois average of 37. In Hamilton, 61% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 36% of Hamilton residents were born in Illinois, 63% were born out of state, 1% were born outside of the United States and 0% were foreign born.