The Hogwarts railway platform in J.K. Rowling’s Harry Potter books is Platform 9¾.
The hidden platform is located at London’s King’s Cross station. Young witches and wizards reach it by running through the barrier between platforms 9 and 10, where they board the Hogwarts Express for the journey to school.
Harry first learns about the platform from the Weasley family in Harry Potter and the Philosopher’s Stone. The magical entrance establishes an important transition between the ordinary Muggle world and the wizarding world.
King’s Cross station did not originally have conventional platforms numbered 9 and 10 beside one another, so the films used a location between platforms 4 and 5 for several shots. The station later installed a commemorative trolley at a real visitor attraction labeled Platform 9¾. The fraction is therefore part of the fictional platform’s distinctive name.