Jerseyville, IL has a population of 8,502 and is the 4,457th largest city in the United States. The population density is 1,644 per sq mi which is 639% higher than the Illinois average and 1714% higher than the national average. The median age in Jerseyville is 41 which is approximately 9% higher than the Illinois average of 37. In Jerseyville, 61% of the population over 15 years of age are married, 97% speak English and 1% speak Spanish. 86% of Jerseyville residents were born in Illinois, 13% were born out of state, 0% were born outside of the United States and 1% were foreign born.