Mount Zion, IL has a population of 5,894 and is the 5,820th largest city in the United States. The population density is 1,397 per sq mi which is 528% higher than the Illinois average and 1442% higher than the national average. The median age in Mount Zion is 40 which is approximately 8% higher than the Illinois average of 37. In Mount Zion, 65% of the population over 15 years of age are married, 95% speak English and 3% speak Spanish. 78% of Mount Zion residents were born in Illinois, 18% were born out of state, 1% were born outside of the United States and 3% were foreign born.