Naperville (/ˈneɪpərˌvɪl/ NAY-pər-vil) is a city in DuPage and Will counties in the U.S. state of Illinois. It is in the Chicago metro area, 28 miles (45 km) west of the city. Naperville was founded in 1831 by Joseph Naper. The city was established by the banks of the DuPage river, and was originally known as Naper's Settlement. By 1832, over 100 residents lived in Naper's Settlement. In 1839, after DuPage County was split from Cook County, Naperville became the county seat, which it remained until 1868. Beginning in the 1960s, Naperville experienced a significant population increase as a result of Chicago's urban sprawl.