The Platform 9 ¾ sign is situated in the western departures concourse of London King's Cross railway station, close to platforms 9 and 10, below the walkway leading to the main building. The ride on the Hogwarts Express starts from King's Cross railway station platform 9 ¾, which is hidden from view, and reached by walking through the barrier between platforms 9 and 10.

Rowling discovered after the books were published that she had confused the layout of King's Cross with that of Euston station, and that platforms 9 and 10 at King's Cross were not the ones between which she had meant her magical platform to be placed.

A wrought iron 'Platform 9 ¾' gate used as part of the film set is preserved at the National Railway Museum. Soon after Alan Rickman's death in 2016 fans created a memorial to the actor at platform 9 ¾.

A Harry Potter-themed store is also located in the station near the plaque.

- Wikipedia