Naperville is a city in DuPage and Will counties in Illinois in the United States. As of the 2000 census, the city had a total population of 128,358; The United States Census Bureau estimated the population in 2006 at 142,901. It is the fourth largest city in the state, behind Chicago, neighboring Aurora, and Rockford. Approximately 95,000 Napervillians live in DuPage County, while about 40,000 reside in Will County. Naperville apartments for rent comparison page shows most up to date rent information on Naperville apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.