Lake Summerset, IL has a population of 1,943 and is the 11,186th largest city in the United States. The population density is 944 per sq mi which is 325% higher than the Illinois average and 942% higher than the national average. The median age in Lake Summerset is 56 which is approximately 50% higher than the Illinois average of 37. In Lake Summerset, 73% of the population over 15 years of age are married, 96% speak English and 1% speak Spanish. 62% of Lake Summerset residents were born in Illinois, 33% were born out of state, 1% were born outside of the United States and 4% were foreign born.