Aurora, a suburb of Chicago, is a city in DuPage, Kane, Kendall, and Will counties in the U. S. state of Illinois. Located primarily in DuPage and Kane counties, it is an outer suburb of Chicago and the second most populous city in the state, and the 115th most populous city in the country.
The population was 197,899 at the 2010 census, and was estimated to have increased to 200,965 by 2017. Once a mid-sized manufacturing city, Aurora has grown since the 1960s. Founded within Kane County, Aurora's city limits and population have expanded into DuPage, Will, and Kendall counties. Between 2000 and 2003, the U. S. Census Bureau ranked Aurora as the 34th fastest-growing city in the United States. From 2000 to 2009, the U. S. Census Bureau ranked the city as the 46th fastest growing city with a population of over 100,000. In 1908, Aurora adopted the nickname "City of Lights", because in 1881 it was one of the first cities in the United States to implement an all-electric street lighting system. Aurora's historic downtown is located on the Fox River, and centered on Stolp Island. The city is divided into three regions, the West Side, on the west side of the Fox River, the East Side, between the eastern bank of the Fox River and the Kane/DuPage County line, and the Far East Side/Fox Valley, which is from the County Line to the city's eastern border with Naperville.