Iroquois, IL has a population of 165 and is the 25,273rd largest city in the United States. The population density is 276 per sq mi which is 24% higher than the Illinois average and 204% higher than the national average. The median age in Iroquois is 51 which is approximately 36% higher than the Illinois average of 37. In Iroquois, 62% of the population over 15 years of age are married, 98% speak English and 0% speak Spanish. 74% of Iroquois residents were born in Illinois, 24% were born out of state, 1% were born outside of the United States and 1% were foreign born.