Lily Lake, IL has a population of 1,253 and is the 13,765th largest city in the United States. The population density is 457 per sq mi which is 105% higher than the Illinois average and 404% higher than the national average. The median age in Lily Lake is 36 which is approximately 3% lower than the Illinois average of 37. In Lily Lake, 65% of the population over 15 years of age are married, 94% speak English and 2% speak Spanish. 76% of Lily Lake residents were born in Illinois, 17% were born out of state, 0% were born outside of the United States and 6% were foreign born.