Aurora is a city in northeastern Illinois, United States. Located primarily in DuPage and Kane counties along the Fox River, it is the second-most populous city in Illinois, after Chicago, and the 144th-most populous city in the U.S. The population was 180,542 at the 2020 census. Founded within Kane County, Aurora's city limits have expanded into DuPage, Kendall, and Will counties. Once a mid-sized manufacturing city, Aurora has grown since the 1960s into a large city within the Chicago metropolitan area. 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 centered on Stolp Island. The city is divided into three regions, the West Side, East Side, and Far East Side/Fox Valley. The Aurora area has some significant architecture, including structures by Frank Lloyd Wright, Ludwig Mies van der Rohe, Bruce Goff and George Grant Elmslie. Aurora is also home to over 50 Sears Catalog Homes and seven Lustron all-steel homes. The Hollywood Casino Aurora, a dockside gaming facility with 53,000 square feet (4,900 m2) and 1,200 gaming positions, is located along the river in downtown Aurora.