Chester, IL has a population of 8,495 and is the 4,428th largest city in the United States. The population density is 1,463 per sq mi which is 533% higher than the Illinois average and 1515% higher than the national average. The median age in Chester is 37 which is approximately equal to the Illinois average of 37. In Chester, 39% of the population over 15 years of age are married, 96% speak English and 3% speak Spanish. 78% of Chester residents were born in Illinois, 20% were born out of state, 0% were born outside of the United States and 2% were foreign born.