Lake in the Hills, IL has a population of 28,908 and is the 1,483rd largest city in the United States. The population density is 2,791 per sq mi which is 1155% higher than the Illinois average and 2980% higher than the national average. The median age in Lake in the Hills is 36 which is approximately 5% lower than the Illinois average of 37. In Lake in the Hills, 60% of the population over 15 years of age are married, 84% speak English and 7% speak Spanish. 73% of Lake in the Hills residents were born in Illinois, 16% were born out of state, 1% were born outside of the United States and 10% were foreign born.