The Norske Nook in Osseo, Wisconsin, serves the best pie I've ever eaten, and many would agree. The winner of numerous national competitions ("23 and counting," the website
boasts) and international acclaim (as evidenced by the thank-you letters from foreign dignitaries that hang on the restaurant's walls), the pies at the Nook are likely better known than the town, if not the county, they're made in. Northern Illinoisans who vacation in upper Wisconsin talk about the restaurant as the stuff of legend. Indeed, I heard stories about it for years before I even went there.
In the years that I attended college in Minnesota, I stopped at the Nook at least once a semester. There's an exit for Osseo off I-94, so it wasn't much of a detour on the drive between Saint Paul and Chicago. I never ate before embarking on the trip: it was crucial that I arrived at the restaurant hungry enough to put away two or three or four slices. (I'm sure that the Norwegian and American entrees, which the restaurant serves in addition to pie, are also very good; but the only things I've ordered there have been pie and coffee.)