Batavia is a city in DuPage and Kane Counties in the U.S. state of Illinois. A suburb of Chicago, it was founded in 1833 and is the oldest city in Kane County. As of the 2010 census, the city had a total population of 26,045, which was estimated to have increased to 26,420 by July 2019.
During the latter part of the 19th century, Batavia, home to six American-style windmill manufacturing companies, became known as "The Windmill City." Fermi National Accelerator Laboratory, a federal government-sponsored high-energy physics laboratory, where both the bottom quark and the top quark were first detected, is located in the city.
Batavia is part of a vernacular region known as the Tri-City area, along with St. Charles and Geneva, all western suburbs of similar size and relative socioeconomic condition.