Headmaster's Office

• Type: Office, Residence
• Location: Headmaster's Tower, Hogwarts Castle, Scotland
• Owner/Residents: Hogwarts School of Witchcraft and Wizardry. Notable occupants include Armando Dippet, Albus Dumbledore, Dolores Umbridge (briefly and illegitimately), Severus Snape, and Minerva McGonagall.
• Key Features: Circular room with numerous windows, a collection of portraits of former Headmasters, whirring silver instruments, the Sorting Hat, the Sword of Gryffindor, a Pensieve, and a perch for a phoenix.

The Headmaster's office is a large, beautiful circular room located in one of Hogwarts Castle's main towers. Its walls are lined with portraits of previous Headmasters and Headmistresses, who are magically bound to offer their counsel to the current incumbent. Access to the office is famously guarded by a stone gargoyle that steps aside only when given the correct password. Under Albus Dumbledore's tenure, these passwords were often the names of his favourite Muggle sweets, such as “Sherbet Lemon,” “Cockroach Cluster,” and “Fizzing Whizzbee.” Once past the gargoyle, a spiral stone staircase moves upwards like an escalator, leading to a single, gleaming oak door with a griffin-shaped knocker. The interior is described as being filled with spindle-legged tables supporting an array of delicate, whirring silver instruments of unknown purpose. Albus Dumbledore's office contained a large, claw-footed desk, a tall-backed chair, and, for many years, a golden perch for his phoenix, Fawkes. Key magical objects were stored here for safekeeping, including the Sorting Hat and the Sword of Gryffindor, which was kept in a glass case. Dumbledore also kept his stone Pensieve in a black cabinet within the office. The room itself is imbued with ancient magic, capable of recognizing the legitimacy of the Headmaster; it sealed itself against Dolores Umbridge when she attempted to usurp the position.

The Headmaster's office serves as a crucial setting for exposition, revelations, and pivotal character moments throughout the series.

• In Harry Potter and the Chamber of Secrets, Harry Potter is first brought to the office after being suspected of attacking Justin Finch-Fletchley. It is here he first meets Fawkes and learns of the phoenix's healing tears. During a later visit, the Sorting Hat provides him with the Sword of Gryffindor to fight the Basilisk.
• In Harry Potter and the Goblet of Fire, Harry uses Dumbledore's Pensieve in the office to witness memories of Death Eater trials, gaining crucial insight into the pasts of figures like Igor Karkaroff and Barty Crouch Jr..
• In Harry Potter and the Order of the Phoenix, the office is the scene of Dumbledore's stunning escape from Cornelius Fudge and Dolores Umbridge. After the Battle of the Department of Mysteries, a grief-stricken Harry confronts Dumbledore here, smashing many of the delicate instruments before Dumbledore reveals the full contents of the prophecy.
• In Harry Potter and the Half-Blood Prince, the office becomes the classroom for Harry's private lessons with Dumbledore, where they use the Pensieve to delve into the memories of Lord Voldemort's past to find a way to defeat him. Following Dumbledore's death, his portrait appears on the wall, joining the other former Headmasters.
• In Harry Potter and the Deathly Hallows, Severus Snape occupies the office as Headmaster. He uses his position, and his communication with Dumbledore's portrait, to secretly aid Harry's quest. After Snape's death, Harry uses the Pensieve in the office one last time to view Snape's memories, learning the final, crucial truths of the war. Following Voldemort's defeat, Harry returns to the quiet office to speak with Dumbledore's portrait and make his final decision about the Deathly Hallows, choosing to repair his phoenix feather wand with the Elder Wand and return the latter to Dumbledore's tomb.

• In the film adaptations, the Headmaster's office is a large, multi-levelled set designed by Stuart Craig. It is filled with an astrolabe, a telescope, and thousands of books, many of which were created by binding British phone books in leather. (film)
• The office's ability to seal itself against an unworthy Headmaster like Dolores Umbridge is a powerful example of how Hogwarts Castle itself possesses a form of sentience and protective magic. (Pottermore)