I was actually surprised to find out a while back that it was filmed at a real high school. I always thought it looked like some kind of community college. Suburban California high schools sure are different from the imposing New York structures I attended, or even Los Angeles High School as seen in
Room 222
, although LA High still did have that feeling of a spacious campus quad that we don't get in NYC schools.

How many exterior ghost town sets could there be within driving distance of the San Fernando Valley? I think chances are excellent that they are the same.

I remember reading that it was Reseda. The commentary has someone (can't recall who) say they "thought it was Reseda."
I just wonder where the ghost town was, if it was a real ghost town and not a set. That was one of the best episodes. Wouldn't it be cool if it was the same ghost town as in "Scream"? I can't tell because I haven't seen that movie but I suppose the chances are slim.
yakko

According to the DVD commentary, the location filming was done at Reseda High School. Andrea's classroom, however, was a studio set.