First-Floor Girls' Toilets

The First-Floor Girls' Toilets are a lavatory located on the first floor of Hogwarts Castle. It is in this lavatory that Harry Potter and Ronald Weasley saved Hermione Granger from a mountain troll, marking the beginning of their friendship.

1991
After a Charms class in the morning of 31 October, 1991, Ron, angry at Hermione for lecturing him on the proper pronunciation of Wingardium Leviosa, insulted her behind her back. Hermione, still in earshot, became upset and headed to this lavatory to cry. She remained in the bathroom all that day.

Later that night, Quirinus Quirrell let a mountain troll into Hogwarts Castle, hoping to create a diversion long enough for him to steal the Philosopher's Stone. The troll eventually made its way from the dungeons up to the first floor, heading into this bathroom. Harry and Ron, who had been looking for Hermione to warn her about the troll, locked it inside before realising the room was the same bathroom Hermione was in.

Unlocking the door and running into the room, Harry and Ron found the troll approaching Hermione, destroying the sinks along the wall as it walked. Harry managed to successfully distract the troll by jumping on its back and shoving his wand up the troll's nose. Thinking quickly, Ron then proceeded to knock out the troll by using the Levitation Charm to hit it in the head with its own club.

The commotion caused by this altercation caused several staff members, including Minerva McGonagall, to discover what had happened. After some consideration, the three ended up gaining a net increase of five house points for their adventure, and were sent back to their common room. The lavatory was presumably repaired afterward.

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Philosopher's Stone (film)
 * Harry Potter and the Philosopher's Stone (video game)
 * LEGO Harry Potter: Building the Magical World
 * LEGO Harry Potter: Years 1-4
 * Harry Potter LEGO Sets
 * Harry Potter Trading Card Game
 * Pottermore