Where is Hill Valley?

Question

Many BTTF fans know that Marty, Doc and Jennifer arrive in Hill Valley on October 21st 2015, and were eagerly awaiting that date.

As outlined in this question, they arrive at 4:29PM. However, the Earth is divided into timezones. So, in order to figure out what time 4:29PM on October 21 2015 is around the world in other timezones, we need to know where Hill Valley is, more specifically, what timezone Hill Valley is in.

As I cannot recall a reference to where Hill Valley is, my question is: where is Hill Valley and what timezone does this put it in?

Answer 1

Hill Valley is in California, Pacific time with daylight savings (UTC-0700),

so the moment of truth is

11:29pm UTC.

The following 1885 railroad map, appearing in Back to the Future III (and listed here as a prop), shows that Hill Valley is located in northern California in the Sierra Nevada mountains:

(As @RoyalCanadianBandit points out, the DeLorean also has Californian license plates; however, on its own this is not certain evidence, as the car might have had plates from a different state.)

California is in the Pacific time zone. And daylight saving time in the USA ends on 1 November 2015, so the time was still 1 hour ahead on 21 October. Thus 4:29pm in Hill Valley is 11:29pm UTC.

This is confirmed (non-canonically) by the website Is today Back to the Future Day?, from which a screenshot taken at 8:07pm UTC on The Day (21 October 2015) looks like this:

_{For the pedants: under the rules in effect in 1989 (after the 1986 enactment of PL 99-359 to amend the Uniform Time Act, but before the Energy Policy Act of 2005 - see this Wikipedia article on daylight savings), US Daylight Saving Time would have ended on the last Sunday in October instead of the first Sunday in November. In 2015 this is 25 October, which is still after 21 October, so Daylight Saving Time would still have been in effect and the answer remains the same.}

Answer 2

California, as per this quote from the start of Back To The Future: Part II:

Marty: Alright Doc, what's going on, huh? Where are we? When are we?

Doc: We're descending towards Hill Valley, California at 4:29pm on Wednesday October 21st 2015.

Answer 3

According to the BTTF wiki, Hill Valley was filmed about 6 miles west of Chinese Camp, near Sonora, CA. And certain buildings were in various other locations, such as Pasadena, CA as noted near the bottom of the Hill Valley page.

The Hill Valley page says in-universe, the town is near U.S 8, which is in Wisconsin, and Highway 395, which is in California. There's an intersection of U.S. 6 and Highway 395 near Bishop, CA. There's also an Interstate 8 way south between San Diego, CA and Casa Grande, AZ (about halfway between Phoenix and Tucson).

Grass Valley, CA is a real town, quite a bit north of the others. There an Interstate 80 near Grass Valley, which is similar to U.S. 8, but may be me grasping for connections that aren't there. In-universe, it's supposed to be about 12 miles west of Hill Valley.

Lone Pine, CA is also on Highway 395, and there's a Lone Pine shopping mall in-universe.

Here is a map with Lone Pine, Bishop, Chinese Camp, and Grass Valley all marked as waypoints.

Also, this website has information about visiting a lot of the sites used to film the 1885 version of Hill Valley, which could be pretty cool. Apparently most of it is accessible to the public.

The map posted by rand al'thor has a number of locations, but I can't find any references to most of them out of universe:

• Hill Valley
• Haysville (on the road southeast of Hill Valley)
• Shonash Ravine (bridge west of Hill Valley)
• Carson Spur (the road leading to Shonash Ravine)
• Brides Pond (northwest of Shonash Ravine)
• Grass Valley (west side of the map)
• Indian Galley/Gully (can't quite tell, just east of Shonash Ravine)

I see a few other words, like "trail", "city", or "valley", but I can't make out the important half of the name.

As pointed out by other comments on this page, and the Snopes article, it's definitely set in California somewhere, but I don't think it gets any more specific than that.

Maybe it used to be one location in the past, but after all the time-travel, some residual spacetime artifacts caused the town to get scattered across California?