Deku Elementary

Deku Elementary is a location mentioned in.

Features and Overview
Deku Elementary is never shown in-game, but if Link speaks to Madame Aroma in the Mayor's Residence while in his Deku form, she will assume he is a student of Deku Elementary visiting on a field trip.

Since there are few Deku residents in Clock Town, it is more likely that Deku Elementary is located somewhere in the Southern Swamp.