As others have said, it was shot at the Valley Forge Military Academy, which was right up the street from Radnor Middle School. I was in 7th grade at the time of filming and for a couple weeks there was much excitement about some shots that were to take place right outside the school. A bunch of students got permission from their parents to skip school and be extras in crowd scenes and such. I was desperate to be one of those kids, since at the time I was convinced that I was destined to be a famous actor and this was my chance for a big break. I was to be discovered!
But I wasn’t allowed to skip. Then when the movie came out my parents wouldn’t even let me see it, as it was too violent. Then it was pretty widely understood to suck.
Stupid TAPS.