Location from harry-potter-prisoner-of-azkaban by
The Dursleys' aggressively normal house in Little Whinging, where Harry accidentally inflates Aunt Marge, flees into the night, and catches the Knight Bus to freedom.
Number 4, Privet Drive is where Harry's third year begins — badly. Aunt Marge is visiting, a bulldog of a woman who insults Harry's parents over dinner until Harry's accidental magic inflates her like a balloon. She floats to the ceiling, bobbing against the light fixture, and Harry grabs his trunk and runs. Outside, alone and convinced he's about to be expelled, Harry sees a massive black dog watching him from the shadows — his first glimpse of Sirius in Padfoot form, though he doesn't know it yet. The Knight Bus arrives, a violently purple triple-decker that careens through Muggle traffic to deliver Harry to the Leaky Cauldron, where Cornelius Fudge is suspiciously lenient about the underage magic. The Ministry doesn't want Harry wandering the streets when Sirius Black is on the loose. Privet Drive is the launching pad for everything that follows.
A neat, unremarkable detached house on a street of identical neat, unremarkable houses. Trimmed lawn, clean windows, polished car in the driveway. Harry's small bedroom upstairs, previously Dudley's second room. Hedwig's cage by the window.
Also known as: Privet Drive, 4 Privet Drive, the Dursleys' house, Number Four