Hogwarts is a very beautiful castle that overlooks a lake and a forest. It rests on the top of a hill, hidden away from Muggle view. 

Hogwarts was built by the four founders entirely out of magic. It took three years before they were ready to open it, which was a very short amount of time for a building that large. 

They added many features, including bewitching the ceiling of the Great Hall to look like the sky outside, so students could tell what time it was and what the weather was like even if they weren't outside. Hogwarts also includes moving stairs and hidden doors.