St. Charles is a city in DuPage and Kane counties in the U.S. state of Illinois. It lies roughly 40 miles west of Chicago on Illinois Route 64. According to a U.S. Census Bureau estimate in July 2012, the city had a total population of 33,327. The official city slogan is Pride of the Fox, after the Fox River that runs through the center of town. St. Charles is part of a tri-city area along with Geneva and Batavia, all western suburbs of similar size and relative socioeconomic condition.