A common room is a shared lounge area in Hogwarts School of Witchcraft and Wizardry. There is one for each house. The common rooms feature fireplaces and sitting areas and are decorated in house colours. They are often used to do homework and to socialize with housemates. The boys' and girls' dormitories are also attached to the common rooms, with spells in place to prevent male students from entering the girls' dorms.
The four houses each have a protective measure to prevent students from other houses entering. To enter the Gryffindor Tower and the Slytherin Dungeon, one requires a password. The Ravenclaw Tower requires the answer to a riddle in order to enter, and the Hufflepuff Basement requires tapping the barrel 'two from the bottom, middle of the second row' in the stack of barrels near the kitchen corridor, in the rhythm of Helga Hufflepuff.
It can be said that the methods of gaining entry to each house's common room mirrors the perceived intellectual reputation of each house. Hufflepuff, often known as the house with no certain particular aptitude in its students, has a very simple method of entry that never changes. On the other end of the spectrum, Ravenclaw, a house prizing intelligence, provides a new intellectual challenge with each attempted entry.
The only common room Harry Potter hasn't visited is the Hufflepuff.
- "Why are they called Common [sic] rooms when only people from a certain house can go into them? Doesn't that make them uncommon rooms?"
- —A Ravenclaw student reflects on the name "common room".[src]
- Gryffindor common room — located in Gryffindor Tower, through the Fat Lady's portrait.
- Hufflepuff common room — located in Hufflepuff Basement, below ground level behind a stack of barrels near the kitchens.
- Ravenclaw common room — located in Ravenclaw Tower, beyond a bronze eagle-shaped knocker that poses a riddle.
- Slytherin common room — located in Slytherin Dungeon, below ground level beyond a stone wall.
Behind the scenes
- The Hufflepuffs are the only house to have a defence mechanism for their common room. If someone taps the wrong barrel or the wrong rhythm, they are doused in vinegar.
- The location of common rooms other than one's own is generally secret to Hogwarts students. Harry Potter learned of the location of two common rooms other than Gryffindor's only through extraordinary circumstances-- the usage of Polyjuice Potion to transform into Gregory Goyle in his second year to follow Draco Malfoy to the Slytherin common room and by consent of Luna Lovegood to the Ravenclaw common room to observe a model of Rowena Ravenclaw's diadem just before the Battle of Hogwarts. When Harry, Ron and Hermione were snatched by Fenrir Greyback's Snatcher gang, Harry replied "Slytherin" when asked what House he was in at Hogwarts. Scabior stated that it was funny how everyone thought that was what they wanted to hear, but nobody they had snatched could tell them where Slytherin's common room was. Harry's correct answer nearly saved him and the others, until Hermione was recognised from a photo in the Daily Prophet.
- Harry Potter and the Philosopher's Stone (First appearance)
- Harry Potter and the Philosopher's Stone (film)
- Harry Potter and the Philosopher's Stone (video game)
- Harry Potter and the Chamber of Secrets
- Harry Potter and the Chamber of Secrets (film)
- Harry Potter and the Chamber of Secrets (video game)
- Harry Potter and the Prisoner of Azkaban
- Harry Potter and the Prisoner of Azkaban (film)
- Harry Potter and the Prisoner of Azkaban (video game)
- Harry Potter and the Goblet of Fire
- Harry Potter and the Goblet of Fire (film)
- Harry Potter and the Order of the Phoenix
- Harry Potter and the Order of the Phoenix (film)
- Harry Potter and the Order of the Phoenix (video game)
- Harry Potter and the Half-Blood Prince
- Harry Potter and the Half-Blood Prince (film)
- Harry Potter and the Half-Blood Prince (video game)
- Harry Potter and the Deathly Hallows
- Harry Potter and the Deathly Hallows: Part 2 (Mentioned only)
- LEGO Harry Potter: Characters of the Magical World (Mentioned only)
- LEGO Harry Potter: Years 1-4
- Harry Potter Trading Card Game
- Pottermore (Mentioned only)