Hogwarts

Hogwarts is a boarding school, founded about a thousand years ago by two wizards and two witches: Godric Gryffindor, Salazar Slytherin, Rowena Ravenclaw, and Helga Hufflepuff. The school is divided into four "houses", each bearing the last name of its founder. At the beginning of each school year, the magical Sorting Hat is placed on each new student's head, and the Sorting Hat announces the house that the student is bound to join. Before it begins sorting, the Sorting Hat sings a short ballad about the founding of the school and the four houses; the song is slightly different every year.

Hogwarts is set in a castle hard by a mountain lake. Although its precise location is not specified in the books, the author has said it is in Scotland[1]. Hogwarts is reached by a train called the Hogwarts Express. Upon arrival, first year students are led by groundskeeper Hagrid on the traditional cruise across the lake.

There are magical creatures in the lake (a giant squid is often seen near the surface, and a colony of merfolk inhabits the bottom) and in the forest (centaurs, giant spiders). The forest is strictly off-limits to all students.

No apparation (apparating and disapparating) is possible on the school grounds, although adults seem to show up by means other than the school train; perhaps they use brooms. The school has strong charms around it to repel "Muggles" (non-magic people).

Albus Dumbledore, headmaster of Hogwarts is an elderly, white-haired gentleman with a droll (some might say silly) sense of humour and twinkling eyes. He always seems to know what's going on at the school and takes a special interest in Harry. He carries no courseload, but formerly taught Transfiguration.

The assistant headmistress is Professor Minerva McGonagall, rather severe in aspect but not hated by the students. She teaches Transfiguration and is head of Gryffindor house.

The Potions master is Severus Snape, despised by many students, except those in Slytherin, his house.

There are several teachers (called professors), each specialising in a single subject. There's a school nurse and at least three greenhouses.

The houses

Gryffindor

Gryffindor is Harry Potter's house at Hogwarts, where he shares a room with Ron Weasley, Neville Longbottom, Seamus Finnigan[?], and Dean Thomas[?]. The entrance is guarded by a painting of a fat lady in pink, who permits entry only after being given the correct password. There is a large common room, with a fireplace, and two staircases leading up to the boys' and girls' dormitories. The Gryffindor ghost is Nearly Headless Nick. Their mascot is the lion. Griffindor's colours are gold and dark red. Gryffindors are known for their courage. Professor McGonagall is the head of Gryffindor.

Hufflepuff

Hufflepuff's colours are yellow and black, and its mascot is the badger. The traditional traits of Hufflepuff students are loyalty, patience, hard work, and justice. Hufflepuffs are sometimes unfairly stereotyped by the other houses as being unintelligent or meek. Cedric Diggory was their Quidditch captain and seeker. The Hufflepuff ghost is the Fat Friar[?]. Professor Sprout is the head of Hufflepuff.

Ravenclaw

Ravenclaw's colours are blue and bronze (silver in the films) and their mascot is the eagle. This house includes Penelope Clearwater[?], Percy Weasley's girlfriend and Cho Chang, Harry Potter's crush and seeker for the Ravenclaw Quidditch team. Their house ghost is the White Lady[?]. The house is known for its academic achievements. Professor Flitwick is the head of Ravenclaw.

Slytherin

The emblematic animal of Slytherin is the serpent and their colours are green and silver. Its head is Severus Snape. Among its more infamous students are Draco Malfoy and Tom Riddle. It is said that most of those who went to Lord Voldemort's side were former Slytherins. The Bloody Baron[?] is the Slytherin ghost. Their traits are ambition, cunning, slyness, and doing anything to achieve the goals which they want.

References

[1] "Hogwarts ... Logically it had to be set in a secluded place, and pretty soon I settled on Scotland in my mind." Fraser, L., An interview with J.K.Rowling, Mammoth, London, 2000. ISBN 0-7497-4394-8. pp 20-21. Additionally, in Fabulous Beasts and Where To Find Them[?], the author mentions that a nest of horrific giant spiders has been rumoured to exist in a forest in Scotland. There is an annotation by Harry or Ron that says "confirmed by Harry Potter and Ron Weasley". This is thought to refer to their meeting with Aragog in Harry Potter and the Chamber of Secrets.