Lerna, IL has a population of 272 and is the 22,979th largest city in the United States. The population density is 2,326 per sq mi which is 946% higher than the Illinois average and 2468% higher than the national average. The median age in Lerna is 34 which is approximately 10% lower than the Illinois average of 37. In Lerna, 55% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 87% of Lerna residents were born in Illinois, 13% were born out of state, 0% were born outside of the United States and 0% were foreign born.