St. Charles is a city in DuPage and Kane counties in the U.S. state of Illinois. It lies roughly 40 miles (64 km) west of Chicago on Illinois Route 64. Per the 2020 census, the population was 33,081. 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 socioeconomic condition.

Kane County is a county in the U.S. state of Illinois. According to the 2020 census, it has a population of 516,522, making it the fifth-most populous county in Illinois. Its county seat is Geneva, and its largest city is Aurora. Kane County is one of the collar counties of the metropolitan statistical area designated "Chicago–Naperville–Elgin, IL–IN–WI" by the US census.