At the beginning of Back to the Future, it is clear that in 1985 Marty McFly knows where Doc Brown lives.

Why then did he look up Doc Brown's address in a 1955 phone book? Doesn't he already know where the Doc lives?

  • 35
    Is there anything in the movie that indicates that Doc Brown never moved house during those 30 years?
    – racraman
    Commented Nov 13, 2020 at 8:49
  • @racraman: As the accepted answer illustrates, Doc did not move far: merely 6 address numbers down the same block on the same street. Had Marty simply had walked to Doc's 1985 address, he easily would have found Doc's 1955 mansion.
    – DrSheldon
    Commented Nov 14, 2020 at 3:32
  • 1
    I'd be surprised if in a small town like Hill Valley you would even have any need to check a phonebook to find anyone as eccentric as Doc Brown: everybody and their dog would know were he lived.
    – Trunk
    Commented Nov 14, 2020 at 18:44
  • 1
    @DrSheldon while that's true, Marty presumably didn't know that until he went there. Commented Nov 16, 2020 at 12:19
  • 1
    Doesn't Marty actually try to ring Doc? Commented Dec 26, 2021 at 20:42

3 Answers 3


In the beginning of the movie, when we see all the clocks, there is a shot of framed newspaper clippings (the mansion burned down on August 1, 1962). Marty has probably read this at some point.

newspaper clippings

Doc's address in 1955 is shown as 1640 Riverside Drive:

Riverside Drive

Garage 1955

Doc's house we see in the beginning of the movie, in 1985, seems to be the garage of the mansion:

Garage 1985

Notice the number on the fence:

Garage 1646

It seems like in 1985, Doc is living in the garage of his former mansion, with the house number "1646", instead of "1640".

Also, by 1985, Riverside Drive has been renamed John F. Kennedy Drive (this is mentioned in the scene where Marty has Dinner with the Baines family), which is why Marty doesn't recognize that it's basically the same address.

  • 13
    Great answer, never noticed this. Even if Marty is fully aware that Doc is living in his former garage, it's conceivable he'd still need directions there if the street layouts have changed and things look very different - the route he'd normally take there might not even exist yet. Marty probably realizes he certainly cannot look for JFK Drive in 1955, much less ask anyone else how to get there, so he could still need the address even if he already knows the location of 1955 Doc's mansion.. Commented Nov 13, 2020 at 17:18
  • 2
    Is there a hidden implication that the house burned down as a result of an early failed experiment on developing the time machine? We know the DeLorean leaves burning tire tracks - if he hadn't come up with the idea of attaching the device to a car yet, it could be disastrous to attempt that indoors. And the timeline adds up - Doc came up with the idea in the mid-50's, and the house burned down in '62, seems to make sense there... Commented Nov 13, 2020 at 20:38
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    John F. Kennedy Drive? They named a street after Joe Kennedy's kid? Commented Nov 13, 2020 at 21:06
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    @DarrelHoffman The leading theories are either that Doc Brown burned it down for the insurance money, or that he did so for some time paradox reasons which I don't fully understand. Either way, the implication is that Doc himself burned down the mansion on purpose. movies.stackexchange.com/questions/78174/… Commented Nov 13, 2020 at 21:44
  • It's interesting that Marty chose to search for Doc's address before going to the location that he knew from 1985. He shows some foresight by considering that Doc may have moved at least once in 30 years. The 1985 residence, located in urban sprawl, looks nothing like a mansion with 435 acres of land (as stated in the newspaper).
    – Hoytman
    Commented Nov 16, 2020 at 16:42

He knows where Doc Brown lives in 1985. There's no guarantee that he lived in the same house 30 years ago. Indeed, it seems that he didn't, because once Marty finds his address, he has to (try and) ask for directions to it.

Marty: Do you know where 1640 Riverside--
Lou: Are you gonna order something, kid?

He wouldn't need to ask where 1640 Riverside was if that was still Doc's address in 1985.


Adding to the previous answer which is essentially correct that Marty didn't knew the previous address. It may be because of following reason:

The 1985 Doc Brown lived in a house which was way smaller than the mansion which Doc has supposedly owned back in 1955.

Maybe Marty knew that the mansion was burnt down and Doc who was once wealthy went broke.

Although initially wealthy because of his inheritance, he spent his entire family fortune on his time travel project. When the Brown mansion was destroyed by fire in 1962 and the property sold to developers, Doc subsequently resided in the mansion's garage. Once broke, he established a privately owned business to offer 24-hour scientific services, building ingenious devices for his customers.

But back in 1955 he owned a mansion and hence Marty sought phone book for Doc's address.

But most importantly Marty was shell-shocked by the different/transformed(not yet developed) Hill Valley and didn't know where to look for Doc Brown.

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