Hogwarts Castle was a large, seven-storey high building supported by magic, with a hundred and forty-two staircases throughout its many towers and turrets and very deep dungeons.
The castle was built in the late Early Middle Ages (c. 993) by a wizard architect and the four most celebrated wizards of the age: Godric Gryffindor, Helga Hufflepuff, Rowena Ravenclaw and Salazar Slytherin. The castle was the main building of Hogwarts School of Witchcraft and Wizardry, regarded as the finest wizarding school in the world.
Hogwarts was built in a valley area — surrounding mountains were part of the landscape — with the fairly large Great Lake to the south of the main building. The huge main oak front doors that led into the Entrance Hall faced west, and opened up to sloping lawns. The deep Forbidden Forest extended around to the west of the castle.