Henderson, IL has a population of 227 and is the 23,886th largest city in the United States. The population density is 856 per sq mi which is 285% higher than the Illinois average and 845% higher than the national average. The median age in Henderson is 52 which is approximately 38% higher than the Illinois average of 37. In Henderson, 64% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 85% of Henderson residents were born in Illinois, 15% were born out of state, 0% were born outside of the United States and 0% were foreign born.