Carlock, IL has a population of 583 and is the 18,608th largest city in the United States. The population density is 1,363 per sq mi which is 513% higher than the Illinois average and 1404% higher than the national average. The median age in Carlock is 35 which is approximately 6% lower than the Illinois average of 37. In Carlock, 55% of the population over 15 years of age are married, 99% speak English and 1% speak Spanish. 87% of Carlock residents were born in Illinois, 13% were born out of state, 0% were born outside of the United States and 0% were foreign born.