Mount Olive, IL has a population of 1,980 and is the 11,081st largest city in the United States. The population density is 1,717 per sq mi which is 672% higher than the Illinois average and 1795% higher than the national average. The median age in Mount Olive is 39 which is approximately 3% higher than the Illinois average of 37. In Mount Olive, 56% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 81% of Mount Olive residents were born in Illinois, 18% were born out of state, 0% were born outside of the United States and 0% were foreign born.