Wisconsin is associated with cheese because the state historically produced more dairy products than other American states, giving it the nickname "America's Dairyland."  The use of the term "cheesehead" as a derogatory word for Wisconsinites originated with Illinois football and baseball fans to refer to opposing Wisconsin sports fans. The term, however, was quickly embraced by Wisconsinites and is now a point of pride. 
Rose Bruno first saw a cardboard "cheesehead" hat at a Milwaukee Brewers vs. Chicago White Sox game in Chicago in 1987 worn by fellow Milwaukeean Amerik Wojciechowski.   Ralph Bruno later made the first one out of foam while he was cutting up his mother's couch. It was made popular by center-fielder Rick Manning, who saw the hat while playing.   Bruno started a business to sell the hats as novelties. The "Cheesehead" trademark is owned by Foamation, Inc. of St. Francis, Wisconsin, which began manufacture of the wearable, foam "Cheesehead" in 1987. It has also been referred to as a "Cheese Hat" since it is legally a hat. 
kaaskop, Dutch for "Cheesehead", is used as a slanderous term towards Dutch people.  The use started as early as World War II, when German soldiers were known to call the Dutch "cheeseheads".  The term "cheesehead" was used in a derogatory manner in the 1969 novel Papillon to describe the jury that sentenced Papillon to life in prison.  
- Kapler, Joseph, Jr. " On Wisconsin Icons: When You Say 'Wisconsin', What Do You Say?" Wisconsin Magazine of History, vol. 85, no. 3 (Spring 2002), pp. 18-31.
- Kane, Joseph Nathan; Alexander, Gerard L. (1979).
Nicknames and sobriquets of U.S. cities, States, and counties. Scarecrow Press. p. 412.
Wisconsin – America's Dairyland, The Badger State ... The Copper State ...
- Foamation: About Us, archived from the original on 2009-03-02.
- Foamation, Inc. v. Wedeward Enterprises, Inc., 947 F.Supp. 1287 (E.D. Wis. 1996)
- Cigelske, Tim (September 8, 2005), "When I was 30: Michael Bednar: Cheeseheads were spreading", MKE, archived from the original on August 1, 2007.
- "Greg Garber News, Videos, Photos, and PodCasts - ESPN". ESPN.com.
- "State honors cheesehead hat creator".
- Prunty, Brendan (January 19, 2008), "The Origin of the 'Cheesehead'", The Star-Ledger.
- Cheddar shredder - Chicago Tribune, 26 December 2013
- "What is a Cheesehead?". Wise Geek. Retrieved 11 May 2018.
- Prescott, Peter, Encounters with American Culture (1963-1972), Transaction Publishers, p. 218, ISBN 1-4128-0496-5. "... and the stupiditiy of a dozen "cheesehead" jurors who couldn't care less."
- Charrière, Henri. Papillion. France: Hart-Davis, MacGibbon Ltd. p. 3. ISBN 0-06-093479-4. "Look at them, there in front of you. Can you see them clearly, those dozen cheeseheads brought to Paris from some distant village?"