Gregory House uses the fictional apartment number 221B in House M.D.
The address is a direct reference to 221B Baker Street, the London home traditionally associated with Sherlock Holmes. House is modeled in part on Holmes, and the series builds several parallels between the two characters: both are brilliant investigators, use unconventional reasoning, and have a close friend named Wilson or Watson.
House’s apartment number is shown as 221B on the series. The reference is not merely a location detail; it signals the show’s detective-story design, in which medical symptoms function like clues and diagnosis takes the place of solving a crime.
Some viewers may remember House’s apartment location without recalling the letter. The canonical Holmes reference is specifically 221B, not 221A or another nearby number. The address is fictional within House M.D.’s setting, even though 221B Baker Street is a famous literary address in London.