Mikoto Elementary is where Satoru completed his primary education. In 1988, the school was subjugated to controversies, after two of its students were kidnapped and murdered. Upon discovering his mother's murder, Satoru is sent back in time to February 15, 1988 by a large-scale Revival.
The school is in Hokkaido, as mentioned in Episode 1, and can also be hinted because of the heavy snow. It could be possibly in the outskirts of Hakodate, as Mt. Hakodate has been mentioned.