221B Baker Street is the address of House's apartment and home throughout the series. The address was deliberately chosen to match that of legendary fictional detective Sherlock Holmes. In Season 1, House's apartment was depicted as having a door that opened directly to the outside. However, in all other seasons, the apartment is part of a low-rise multiplex and his front door opens onto a hallway. House's apartment is the first one on the left, directly inside the door.
House's apartment appears to be a one-bedroom with a living room, bathroom and full kitchen. Although the layout is simple, all the rooms are quite spacious. According to Wilson in Season 3, House has lived at this address for at least twelve years before the series started - before he started working at Princeton-Plainsboro Teaching Hospital. The building itself appears to be very old, although it is well maintained. It is not clear if House's unit is a condominium or a rented apartment, but when his pipes broke, he had to pay for the repairs himself, suggesting he has an ownership interest or at least has to maintain the interior himself.
House's living arrangements are very straightforward, with tasteful but functional furniture. His only luxury is a grand piano which he plays frequently. His living room contains several bookcases, all of which are filled with medical texts plus a few personal mementos, like his yearbook. Although cluttered, the interior is kept fairly neat (unlike Holmes, whose apartment often appeared as if a hoarder resided there and the space was in a constant state of disarray).
Two things are usually found in abundance in House's apartment - sneakers (his closet is generally full of them) and Vicodin (which is hidden nearly everywhere). As such, House does not like it when people "mess with his stuff". When Alvie sold some of his possessions, House paid several times what they were worth to get them back.
House's apartment appears to be about eight miles from the hospital - House ran the distance in Meaning when his leg pain disappeared.