Context: Development of the film began in 1993 before the novel was published. Mike Nichols purchased the film rights, and the project was picked up by Savoy Pictures. After Nichols stepped down, the film adaptation became mired in development hell; during the troubled pre-production, Ben Stiller and John Dahl turned down opportunities to direct the film. After Savoy closed in November 1995, the project was sold to Paramount Pictures, and financed by Mutual Film Company, which provided a budget of $17 million. John Boorman was hired to direct, but scheduling conflicts led to his replacement by Raimi. Principal photography began in January 1998 and concluded in March after 55 days; filming took place in Wisconsin and Minnesota. The score was produced and composed by Danny Elfman.

Question: where was the movie a simple plan filmed?
Steam of consciousness below:
To answer the question, consider the following: Principal photography began in January 1998 and concluded in March after 55 days; filming took place in Wisconsin and Minnesota.
So, the answer is Wisconsin and Minnesota.