In J.K. Rowling’s Harry Potter books, the Hogwarts Express leaves from Platform 9¾. The hidden platform is located at London’s King’s Cross railway station and is reached by passing through a barrier between platforms 9 and 10.
Harry first learns about the platform while traveling to Hogwarts for the first time. The Weasley family helps him find it, and the magical barrier becomes one of the series’ recognizable entrances between the ordinary Muggle world and the wizarding world.
King’s Cross station does not have a real platform 9¾ in the standard railway numbering system. However, the station has hosted Harry Potter-themed signs and a luggage trolley installed against a wall, allowing visitors to pose as though they are passing through the barrier.
The Hogwarts Express itself is a scarlet steam train that carries students north to Hogsmeade near Hogwarts. Students normally board it on 1 September, the start of the school year in the novels.