|"Then he waved the wand once, and the letters of his name rearranged themselves..."|
|"Is this all real? Or has this been happening inside my head?"
The subject of this article is a real-life person, group, company, product, or creative work that has been mentioned "in-universe" in a canon source. The Harry Potter Wiki is written from the perspective that all information presented in canon is true (e.g., Hogwarts really exists), and, as such, details contained in this article may differ from real world facts.
King's Cross Station is considered one of the main train stations to serve London, England. Students of Hogwarts School of Witchcraft and Wizardry take the scarlet steam engine named the Hogwarts Express to Hogwarts from Platform 9¾ on 1 September at 11 AM sharp. To get to Platform 9 3/4, you run straight at the wall between 9 and 10. It also serves as a major intercity and commuter rail hub for Muggles going to North London or Yorkshire and the North East and Scotland.
When Ottaline Gambol commandeered a Muggle train to serve as the new mode of transport for Hogwarts students, she also had constructed a small station in the wizarding village of Hogsmeade: a necessary adjunct to the train. The Ministry of Magic felt strongly, however, that to construct an additional wizarding station in the middle of London would stretch even the Muggles' notorious determination not to notice magic when it was exploding in front of their faces.
It was Evangeline Orpington, Minister from 1849-1855, who hit upon the solution of adding a concealed platform at the newly built King's Cross station, which would be accessible only to witches and wizards. On the whole, this has worked well, although there have been minor problems over the ensuing years, such as witches and wizards who have dropped suitcases full of biting spellbooks or newt spleens all over the polished station floor, or else disappeared through the solid barrier a little too loudly. There are usually a number of plain-clothed Ministry of Magic employees on hand to deal with any inconvenient Muggle memories that may need altering at the start and end of each Hogwarts term. 
Platforms 9 & 10
Platform 9¾ is the platform from which the Hogwarts Express may be boarded on September 1st. The platform has, on September the first, a sign hanging over it, reading: Hogwarts Express, eleven o'clock, and there is a wrought iron archway bearing the words Platform Nine and Three Quarters over the entry/exit to the platform. At the conclusion of the school year, the Hogwarts Express returns to King's Cross bringing the students of Hogwarts back for their summer holidays. It can be assumed that the sign over the platform changes on the day the train returns from Hogwarts.
In order for someone to get onto Platform 9¾, they must walk directly at the apparently solid barrier dividing platforms nine and ten. Mrs. Molly Weasley advises that one should "do it at a bit of a run if you're nervous." It is not known exactly how Muggles do not, or cannot get onto the platform; however, it can be assumed that powerful magic of some sort is employed in order to keep them ignorant of its existence. However, in Harry Potter and the Deathly Hallows it was shown in Snape's memories that Lily Evans's family was present at the platform as she boarded it, which could mean that Muggles are able to enter the platform, if made specifically aware of its existence.
Usage by Harry Potter
In 1992, Dobby the House-elf did something to the barrier dividing platforms 9 and 10, in order to prevent Harry Potter and Ron Weasley accessing the platform. All that is known about the magic he used is that it somehow made the barrier which acts as entrance/exit to Platform 9¾ solidify, thus causing Harry and Ron to crash into it, as opposed to passing through it as wizards and witches normally did. Consequently, they decided the only way to get to Hogwarts was to steal Arthur Weasley's Flying Ford Anglia and fly it to the school.
In 1998, during the Battle of Hogwarts, Harry Potter allowed himself to be struck with a Killing Curse by Lord Voldemort, and he entered a Limbo state in which his spirit met with the spirit of Albus Dumbledore, at a location that Harry Potter identified as King's Cross Station. The station was, in the unconscious mind of Harry, clean and empty except for something that looked like a small, naked child, curled on the ground, with skin that was raw and rough, as though it had been flayed, which lay under a seat. Dumbledore then revealed to Harry that the form represented a small part of Lord Voldemort, destroyed when he "killed" Harry and thus annihiliated the part of his soul which he had unwittingly implanted in him.
In 2017, Harry, Ginny, Ron, and Hermione sent their children - Rose Weasley, Albus Severus Potter, and James Potter - off to Hogwarts. There, they caught a glimpse of Draco Malfoy and his wife Astoria seeing off their son Scorpius.
Behind the scenes
- J. K. Rowling chose King's Cross Station as the portal that would take Harry to Hogwarts because this was where her parents met on a train to Scotland.
- When writing the Harry Potter books, J. K. Rowling was thinking of Euston train station when she was describing platforms 9 and 10. At King's Cross station, platforms 9 and 10 only offer services on London commuter rail (currently operated by Great Northern and running to North London, Hertfordshire and Cambridgeshire) and are separate to the rest of the station. More importantly, there is nothing between platforms 9 and 10 at the real King's Cross - the platforms exist either side of two parallel railway lines, hence why during the films, platforms 4 and 5 are used. However, Euston station also has it's platforms 9 and 10 existing either side of of two parallel railway lines, and those platforms are only served by suburban and commuter rail services (operated by London Overground and London Midland respectively) too.
- The cover of Harry Potter and The Philosopher's Stone depicts King's Cross with a High Speed Train visible next to the Express. High Speed Trains do not enter the part of the station where Platforms 9-11 are, but the British Rail "Intercity" livery it is depicted with is correct for the 1991 setting of the book.
- It is possible that King's Cross was the place Harry "chose" to meet Dumbledore because the station symbolised Harry's entrance into the wizarding world, or rather, the border that separates the wizarding and Muggle worlds, or also because death is culturally known as "the last travel". Since trains are used to travel, this is a viable theory. However, Harry never "took the train" to the other side.
- In Harry Potter and the Philosopher's Stone, when Harry first meets the Weasleys at King's Cross Station, Mrs. Weasley asked her children "Now, what's the platform number?" This is unusual as not only had she gone to Hogwarts herself, but by this time so had five of her seven children (with two of them completing their education), and she would have gone through the barrier many times. Of course, Mrs. Weasley could have been just testing her children if they knew where to go. Possibly, J.K. Rowling wrote this just to make sure that Harry was talking with the right people.
- In LEGO Harry Potter: Years 5-7, King's Cross is depicted as an underground station that can be accessed via a set of stairs in Charing Cross Road. In reality, King's Cross St Pancras is a separate, but directly connected underground station.
- At the real King's Cross, there is half of a luggage cart in the western departures concourse (it has moved at least twice), and there is a sign that says Platform 9¾ so tourists can take pictures as if they are disappearing into the barrier.
- The Harry Potter Shop at Platform Nine and Three-Quarters is found at the real King's Cross Station in London, England.
- The exterior shots seen in the movies are of neighbouring St Pancras, whose Gothic style was considered far more impressive than the 1960s look that the station then had - King's Cross has since undergone a major renovation.
- Harry Potter and the Philosopher's Stone (First appearance)
- Harry Potter and the Philosopher's Stone (film)
- Harry Potter and the Philosopher's Stone (video game) (Mentioned only)
- Harry Potter and the Chamber of Secrets
- Harry Potter and the Chamber of Secrets (film)
- Harry Potter and the Chamber of Secrets (video game) (GBC version only)
- Harry Potter and the Prisoner of Azkaban
- Harry Potter and the Prisoner of Azkaban (film)
- Harry Potter and the Prisoner of Azkaban (video game) (Mentioned only)
- Harry Potter and the Goblet of Fire
- Harry Potter and the Order of the Phoenix
- Harry Potter and the Order of the Phoenix (film)
- Harry Potter and the Half-Blood Prince
- Harry Potter and the Deathly Hallows
- Harry Potter and the Deathly Hallows: Part 2
- LEGO Harry Potter: Building the Magical World
- LEGO Creator: Harry Potter
- LEGO Harry Potter: Years 1-4
- LEGO Harry Potter: Years 5-7
- Harry Potter LEGO Sets
- Harry Potter: The Character Vault
- Harry Potter: The Creature Vault (mentioned only)