Kenilworth, IL has a population of 2,613 and is the 9,578th largest city in the United States. The population density is 4,294 per sq mi which is 1832% higher than the Illinois average and 4640% higher than the national average. The median age in Kenilworth is 42 which is approximately 13% higher than the Illinois average of 37. In Kenilworth, 74% of the population over 15 years of age are married, 91% speak English and 2% speak Spanish. 51% of Kenilworth residents were born in Illinois, 35% were born out of state, 2% were born outside of the United States and 12% were foreign born.