There was a storage basement under the Potions Classroom at Hogwarts Castle. It was accessible via a trapdoor and it was used to store extra cauldrons, ingredients and phials.

Hidden by a portrait of fruit tickle the pear and it will open up to the kitchens. The Kitchens are huge, and run by house-elves and it's where they cook all the meals. Although, you're not supposed to enter, the elves really don't mind.

The Slytherin Dungeon is located behind a wall in the cellars of Hogwarts School of Witchcraft and Wizardry. A password spoken to the wall is required to enter it; whereupon a passage is revealed leading to the common room -- a low-ceilinged, dungeon-like room with greenish lamps and chairs. This dungeon extends partway under the lake. It has quite a grand atmosphere, but also quite a spooky, cold one.

The Hufflepuff Basement is located behind a still-life portrait of a fruit bowl near the kitchens of Hogwarts Castle. A password is presumably required to enter it, which is spoken to the portrait. A hole or passage-way is behind the painting, leading to the common room, which is a room where Hufflepuff students can relax after a long day of studying. The common room is full of fat armchairs, yellow hangings, and probably a bulletin board where school notices, ads, lost posters, etc. can be posted.

This is one of the various bathrooms here throughout the castle. It's obviously girls only (just as the boy's bathroom is boy's only). This is where, well never mind you should have a good idea.

Where all the Potion Ingredients are located. Do NOT let any professor catch you in here without permission, it won't be very pretty especially if it's the potions professor who catches you.

The Herbology Store is a room used to store Herbology equipment. Its walls are covered in shelves filled with boxes, shears, pots, jars, among other items. This storeroom connects the Training Grounds to the Herbology Greenhouses.

The Portrait Room is a room off the Entrance Hall, in Hogwarts Castle. It's exactly what it says, a room where a number of portraits hang. Several portraits are secret passageways to the upper levels.

This is the Staff Room and where you'll find the staff if they aren't in class or their office or living quarters. It has mismatched wooden dark chairs. there's even a Boggert in here, as well. They keep it here for the defense classes.

An old Classroom which is no longer being used by anyone. In fact it hasn't been used in a very very long time. Students are seen here from time to time, but you have to be careful just in case a prefect or professor is around.

Come visit moaning Myrtle. She likes visitor well when your nice that is, and if she isn't upset. You'll know when she's upset, because she tends to flood the bathroom making it go out into the hallway.

The Chamber of Secrets was allegedly created under the dungeons of Hogwarts Castle during Medieval times by Salazar Slytherin, who disagreed with the other Hogwarts founders on the merits of blood purity. The Chamber of Secrets was home to an ancient Basilisk, which, according to legend, was intended to be used to purge the school of Muggle-born students. The Chamber is lined with statues of snakes, and a large statue of Salazar Slytherin is at the center.

This is a place where all the houses can come to hang out and looks like all the other common rooms, except this one you don't have to give a password to. It was added to support house unity and get the students to spend more time with one another.

This is the entrance to the headmaster's office. Just speak the password aloud and the Griffin shall move, revealing a stair case that you can climb up to the Headmater's Tower. Next, all you have to do is knock on the door and wait for him to answer.

The head nurse is extremely protective of their patients. You better not enter those double doors unless you need their attention. Also, please note they also keeps a good eye on them as well, so escaping might be difficult.

Head Nurse: Open.

Come check out a book at the Library. Be very quiet or Madam Pince might just kick you out. Also, make sure she doesn't see you mistreat any of the books, she'll flip out about that too. The library closes at 8 every night.
Librarian Open.

Only older students 6th year and above are allowed here unless you have a note from a teacher and you're here for a very important reason. The books in this section are a lot more dangerous and due to that they usually only let the older students in here.

The Trophy Room is a room on the third floor of Hogwarts. Awards, trophies, cups, plates, shields, statues, and medals are kept in crystal glass displays in this room. This room also contains a list of Head Boys and Head Girls. Prominently displayed are Hogwarts Awards for Services to the School.

This is where you're characters will do all their studying, if they don't want to do it in their dorm rooms that is. It's an area in the back of the Library and away from everyone else so that it's quiet and one can concentrate.

Here's where the staff restroom is located. It's the only staff restroom here, and it's open. The staff could use the normal bathrooms as well, but they have their own personal one too.

The Mirror of Erised shows us nothing more or less than the deepest, most desperate desire of our hearts. The happiest person in the whole world would look in the mirror and see a reflection of exactly the way he or she is. Inscribed across the top of the frame is the following text: Erised stra ehru oyt ube cafru oyt on wohsi Reversing the inscription and rearranging the spaces produces: I show not your face but your heart's desire It can be very very dangerous though, so be careful.

This is one of the various bathrooms here throughout the castle. It's obviously boys only (just as the girl's bathroom is girl's only). This is where, well never mind you should have a good idea.

The Muggle Studies showroom was a room serving as an antechamber to the Muggle Studies Classroom on the fifth floor of Hogwarts Castle. This room was very spacious and square in shape. On two of the four corners of the room stood dioramas depicting parts of an ordinary Muggle household (such as a living room), and next to which blackboards with explicative diagrams (depicting how Muggles use recliners and the safety distance kept from the screen while watching television). Many other Muggle artifacts are kept in showcases or against the walls, such as radios, post boxes and vaccum cleaners. From the arched ceiling hang magic-powered lightbulbs.

The Wizard Card Collectors' Club room is a spacious room at Hogwarts Castle where the Wizard Card Collectors' Club meets. It is located on the fifth floor. The space is usually messy and has a laid-back atmosphere, with posters and announcement boards on the walls. The room contains a large main area for meetings, trading cards and playing card games. There is also a backroom containing locked chests with prizes that can only be acquired by collecting specific Chocolate Frog Card sets.

The Prefects' bathroom is a special bathroom on the fifth floor of Hogwarts restricted to use by school Prefects, Head Boys, Head Girls and Quidditch captains. It is located on the fifth floor behind the fourth door to the left of a statue of Boris the Bewildered, which only opens when given the correct password.

The Room of Rewards is a secret room at Hogwarts School of Witchcraft and Wizardry that notes students' various achievements. It can be accessed via the portrait of Vindictus Viridian on the Grand Staircase. It is not to be confused with the Trophy Room.

Also known as the come and go room. It was named that by the house elves in the kitchen. The room will only appear to someone who really needs it. You need to walk across the tapestry 3 times and tell it exactly what you want, then a door will appear.