Gregory House’s apartment number on Baker Street in House M.D. is 221B.
The address is a deliberate reference to Sherlock Holmes, the fictional detective whose methods and personality strongly influence House. Both characters are brilliant observers who use deduction to solve puzzles, have difficult social habits, and are associated with a close companion who helps connect them to ordinary life.
House’s apartment is in New Jersey’s Princeton area within the show’s world, yet its address is written as 221B Baker Street. That combination makes the allusion clear rather than presenting the apartment as a realistic London residence.
The number should not be confused with the fictional hospital’s address or with House’s workplace. 221B Baker Street is best known internationally as Sherlock Holmes’s London address, while House M.D. borrows it as a character detail and literary clue.