As a high school student from the North Shore suburbs of Chicago (specifically Glenview), I would like to mention a few errors in Juliet's writeup. These are all inconsequential, but I’ll correct them all the same.
First off, the high school used for shooting was not Glenview High School as it doesn't exist. The school actually used was Glenbrook North High School. (It serves the suburbs Glenview and Northbrook) This I am sure of. I am a student of this institution's sister school Glenbrook South High School and have visited it many times.
Secondly, I do not believe that Ravinia is a suburb of Chicago. I am, however, certain that Ravinia is the name of an outdoor music venue in Highland Park (which is a suburb). It's still a very worthwhile visit if you ask me, even without any relation to the film.
Finally, I'm pretty sure Sheridan only has one r, but who cares?