Maryville, IL has a population of 7,837 and is the 4,775th largest city in the United States. The population density is 1,468 per sq mi which is 560% higher than the Illinois average and 1520% higher than the national average. The median age in Maryville is 42 which is approximately 13% higher than the Illinois average of 37. In Maryville, 65% of the population over 15 years of age are married, 96% speak English and 1% speak Spanish. 61% of Maryville residents were born in Illinois, 36% were born out of state, 0% were born outside of the United States and 2% were foreign born.