1. Voldemort was 71 years old when he died in the Battle of Hogwarts.
2. And Dumbledore was 115 years old when he was killed by Snape.
3. Fred and George Weasley were born on April Fools' Day.
4. And Harry Potter shares the same birthday as J.K. Rowling, which is July 31.
5. The first time the vanishing cabinet is mentioned is actually in Chamber of Secrets when Peeves broke it.
6. Arthur Weasley was supposed to die in Order of the Phoenix, but was replaced with Lupin and Tonks in Deathly Hallows.
7. And Lupin wasn't originally meant to die, but Rowling knew she needed to bring back the story of parents dying, because leaving a child parentless is one of the most horrific things about war.
8. From the very beginning, J.K. knew she wanted the Battle of Hogwarts to lead to Harry walking to his death in the forest with his family, and having Hagrid carry him out. This is what kept Hagrid safe from dying in the books.
9. Hogwarts has no tuition fees; the Ministry of Magic covers all magical education.
10. Harry and Dudley would still see each other after the Battle of Hogwarts, but they would visit more out of a sense of duty and sit in silence so that their children could see their cousins.
11. Fred was the hardest person for Rowling to kill.
12. George never got over Fred's death — and he was never able to produce a Patronus again.
13. George eventually married Angelina Johnson and named his first child after Fred.
14. The only time the twins ever got injured was when they were apart. George lost an ear while en route to the safe house, and Fred died in an explosion.
15. Rowling almost killed off Ron "out of sheer spite."
16. After the Battle of Hogwarts, Harry, Ron, and Hermione all went to work for the Ministry. Harry and Ron became Aurors, and Hermione began her post-Hogwarts career at the Department for the Regulation and Control of Magical Creatures.
17. Eventually, Harry became Head of the Auror Office, Hermione became Minister of Magic, and Ron left the Ministry to help George run the joke shop.
18. "Hermione" is the female derivative of "Hermes," a messenger god known for his sharp wit and ability to transition between worlds.
19. "Harry" in Norse means "war chief" and in English it means "protector."
20. Ginny Weasley became a professional Quidditch player for the Holyhead Harpies, but eventually retired to take care of her children. She then became a Senior Quidditch correspondent at the Daily Prophet.
21. These were some of the original names of the characters before Rowling changed them: Hermione Puckle, Neville Puff, Draco Spinks, Lily Moon (Luna Lovegood), Madhari Patil, and Mati Patil.
22. Michael Jackson once approached Rowling about making a musical based on the books, but she turned it down.
23. Rowling eventually produced a play with John Tiffany and Jack Thorne called Cursed Child, which tells the story of Harry's son, Albus Severus Potter.
24. Cursed Child won Best New Play at the Olivier Awards, and Best Play at the Tony Awards.
25. For a long time, Rowling planned the last word in the series to be "scar," but eventually changed the last sentence to "All was well."
26. Rowling intended for Hermione to have a younger sister, but it felt "too late."
27. Ron's Patronus is a Jack Russell Terrier, known for chasing otters. Hermione's Patronus is an otter.
28. "Expecto Patronum" translates to "I await a guardian" in Latin.
29. Dementors are based off J.K. Rowling's time of depression in her twenties.
30. Two alternate titles for the final book were Harry Potter and the Elder Wand and Harry Potter and the Peverell Quest. Rowling quickly decided against the latter because it sounded too corny.
31. After the Battle of Hogwarts, the trio all got their own Chocolate Frog cards.
32. The tale of the Deathly Hallows was based on The Pardoner's Tale by Geoffrey Chaucer.
33. Percy ended up as a high-ranking official under Kingsley at the Ministry.
34. J.K. Rowling said Lily might even have grown to love Snape romantically (she certainly loved him as a friend) if he had not loved Dark Magic so much, and been drawn to such loathsome people and acts.
35. After Snape died, he was not immediately added to the portraits in the headmaster's office — but Harry insisted he be placed next to Dumbledore.
36. Most Black family members are named after stars or constellations. Sirius is known colloquially as the "Dog Star," reflecting its prominence in its constellation, Canis Major (Greater Dog).
37. James Sirius Potter, Harry's oldest son, stole the Marauder's Map from his dad's desk.
38. Winky the house-elf is still at Hogwarts, but never got over her addiction to Butterbeer.
39. There are 700 fouls in Quidditch.
40. Originally Dean Thomas thought his father abandoned him, but it turns out that Dean’s dad never told his family he was a wizard, and he was killed when he refused to join Voldemort.
41. Platform 7 1/2 is the Orient Express.
42. Mahoutokoro is the Japanese wizarding school, located on the topmost point of the volcanic island of Minami Iwo Jima. It has the smallest student body of the 11 major wizarding schools.
43. The flying carpet is the main source of transportation in South Asia.
44. A magnificent fountain in the middle of the park at Beauxbatons School is said to have healing and beautifying powers and is named for Nicolas and Perenelle Flamel.
45. Wizards have the power to correct or override "mundane" nature, but not "magical" nature. Therefore, a wizard could catch anything a Muggle might catch, but he could cure all of it; he would also comfortably survive a scorpion sting that might kill a Muggle, whereas he might die if bitten by a Venomous Tentacula.
46. Ilvermorney is the American wizarding school, located at Mount Greylock in Massachusetts.
47. The Houses of Ilvermorney are: Horned Serpent, Wampus, Thunderbird, and Pukwudgie.
48. Newt Scamander had a close relationship with fellow student Leta Lestrange, a relative of Bellatrix.
49. Non-magic people (Muggles) are known as “No-Maj” in America.
50. Luna Lovegood became a naturalist and eventually married Rolf Scamander (Newt Scamander's grandson), with whom she had twin sons, Lorcan and Lysander.
51. Minerva McGonagall was a gifted Quidditch player, but she experienced a nasty fall in her final year at Hogwarts that left her with a concussion and several broken ribs.
52. She ended up marrying her old boss at the Ministry, Elphinstone Urquart. He suffered an accidental death (Venomous Tentacula bite) three years into their marriage. She always kept her maiden name.
53. Dumbledore's boggart is the corpse of his sister, Ariana.
54. And when he looked into the Mirror of Erised, he saw his family alive, whole and happy – Ariana, Percival, and Kendra all returned to him, and Aberforth reconciled with him.
55. "Bellatrix" means "combative" in Latin.
56. The first Harry Potter book was published in 1998, the same year the final Battle of Hogwarts was fought. It opens at the close.
57. Dumbledore understood Mermish, Gobbledegook and Parseltongue.
58. After the Battle of Hogwarts, Umbridge was arrested, interrogated and imprisoned for crimes against Muggleborns.
59. Rita Skeeter is still active, and she wrote a biography of Harry right after the war. "One quarter truth to three quarters rubbish."
60. Mr. Weasley fixed Sirius's motorbike and gave it to Harry.
61. Rowling killed Hedwig because her death represented a loss of innocence and security.
62. Snape was the only Death Eater who could perform the Patronus Charm.
63. Draco’s first name comes from the Latin word for dragon, and is also the name of a constellation in the northern sky. Malfoy is of French extraction, mal foi, and means "bad faith," or "unfaithful."
64. "Petunia" was the name Rowling always gave unpleasant female characters in games of make-believe she played with her sister.
65. Dumbledore fell in love with Gellert Grindelwald.
66. The third smell Hermione recognizes in the Amortentia potion is Ron's hair.
67. Before taking the post of Defense Against the Dark Arts, Quirrell was the Muggle Studies teacher.
68. J.K. Rowling in retrospect thinks Hermione and Ron shouldn't have ended up together.
69. The Elder Wand's core was made from the tail hair of a Thestral.
70. Voldemort's boggart is his own corpse.