Since I already was in the area, I visited the school seen in Kanon. Tamagawa-Jōsui Station is the closest train station.
Image from Episode 2 - 11m56s
This is the school building.
The name of the school. Since this is a real-life school, these were the only 2 pictures I could get without trespassing.
This location was visited on 2014/04/13.
If you decide to visit this place yourself, do remember that it is a school still in use and you should NOT enter it.
School official website
Special thanks to the ones who went here before: