Sandwich is a city in DeKalb, Kendall, and LaSalle counties in the U.S. state of Illinois. The population was 6,509 at the 2000 census. The 2008 population estimate by the U.S. Census Bureau for the city is 7,337.
Sandwich is the home of the Sandwich Fair. Held yearly the Wednesday-Sunday after Labor Day since 1888, it is the oldest continuing county fair in the state of Illinois and is one of the largest antique fairs in the United States, drawing daily crowds of more than 100,000, with the top attendance days reaching more than 200,000 fair-goers.
The Town is also inexorably tied to politician "Long John" Wentworth and his efforts to move the State of Illinois border with Wisconsin from being even with the bottom of Lake Michigan to the current line of where it is now. If the border was not changed, the State Line would actually reside along the LaSalle-DeKalb County border, splitting parts of Sandwich from the main areas of the Incorporated community. The community was established when Almon Gage sought a railroad stop on the BNSF rail line that runs through town. Originally naming it Newark Sation, (not to be confused with nearby Newark), he and Wentworth worked extensively to create the community and also to get the railroad stop created. In honor of his efforts, Wentworth had been given the opportunity to name the town, and he named it after his home of Sandwich, New Hampshire. The Towns neglected Wentworth apartments and Wentworth Street are also named after Mr. Wentworth.