Ndtyhij

This is something that has bothered me for a long time, and this question question reminded of it and motivated me to ask it here.

At the end of Back to the Future III, we see that the ravine formerly known as "Clayton", (after Clara Clayton who originally plunged to her death before Doc Brown went back to 1885 and rescued her, inadvertantly changing history) was now called "Eastwood Ravine". Why was it renamed this?

The implication is that it is because Marty, aka "Clint Eastwood" instead went over the ravine when the stolen train plunged over the edge. Since nobody knew about the Delorian (it was further down the track where nobody in the hijacked train would have seen it) and nobody knew that time travel was involved, it seems at first glance that they just put two and two together and assumed that the man they knew as Clint Eastwood had died.

But there are two problems with this theory. The first is that there were two hijackers, and the other one was known as Doc Brown. Why not call it the Brown Ravine? Doc Brown was a better known member of the community, was an established blacksmith, had his own shop, and even quite a few strange contraptions. "Eastwood" on the other hand had little in the way of ties with the town, and aside from a bit of publicity over his run-in with Buford Tannen (which he escaped alive by his wits, not any superior gun-fighting ability) was a virtual unknown. After he left the people of the town undoubtedly had to deal with his abandoned blacksmith shop, and should have put two and two together and decided Doc Brown was the train hijacker, even in the face of the second problem, which is...

Both Doc Brown and Marty wore masks when hijacking the train. Presumably, this was so their identities would not be known, and not just so they would be seen as serious about taking the train. Doc Brown, not knowing that Clara was coming after him, probably would instinctively not want her to associate him with such a deed after he was gone. In any case, the conductor and engineer on the train would likely not have seen either Doc or Marty before, as their livelihood is aboard the train and they probably did not live in Hill Valley. If they had been through the town enough to be familiar with either of the masked men it would have been Doc Brown, who had been there long enough to become established. Likewise, the other people on the train did not interact with either man so would not have been able to hear their voices or otherwise identify them.

The only person who would probably miss Marty was Séamus McFly, and it seems unlikely that he would put put two and two together and decide Marty stole the train (after his interactions with him, I find it unlikely that he would believe it something that "Clint Eastwood" would do). Even if he did I find it further unlikely that he would go sharing his suspicions with anybody.

So why, when Marty returned to 1985, was the ravine now named "Eastwood" after him?

As you note, Doc and Marty put masks on (bandanas that cover everything below the eyes) before climbing into the locomotive and pointing guns at the engineer (who asks "is this a holdup?", to which Doc responds "It's a science experiment"), so there are no external witnesses who could say for sure who hijacked the train. Therefore, when Doc sails off on the hoverboard with Clara, it seems possible he just returned to his blacksmith position in Hill Valley. It's true Doc was seen riding away from the center of town on horseback with "Clint Eastwood", but he could always say that the two had a falling out when Clint told him of his plan to rob the train, and since the train went over the cliff and would seem to have killed the hijackers, it would be hard for the people of Hill Valley to seriously believe Doc was Clint's accomplice if they saw him alive.

And even if Doc didn't return to Hill Valley, so people put two and two together and realized he and Clint must have been the hijackers, Clint Eastwood would be more likely to become a colorful folk character due to the way he suddenly appeared in town, saved Doc from "Mad Dog" Tannen with a well-aimed pie plate, outsmarted Tannen in a showdown leading to his capture by the law, and immediately ran off to hijack a train, all within a few short days. The dramatic nature of his tale might be enough reason to name the ravine after him rather than Doc if the townspeople thought both had fallen into the ravine, even though they knew Doc better (they might have also figured the man who defeated Tannen was more likely the ringleader of the train hijacking than a kindly old tinkerer like Doc). And of course, if Doc didn't return to Hill Valley but the people there somehow learned that he had survived, in that case they definitely wouldn't name the ravine after him because they only seemed to name it after people who died by falling into the ravine, as Thomas pointed out.

One last minor point is that your title seems wrong to me--it should be "why was the Shonash Ravine renamed Eastwood Ravine?" The change from Clayton to Eastwood Ravine was a change to the timeline, not people "renaming" it--there was never any version of the timeline where it was named Clayton at one date, and then at a later date people decided to change the name to Eastwood. (edit: never mind, I was thinking of "renamed" from an in-universe perspective, but as you say in your comment, it was renamed from the perspective of the audience watching the movie.)

I would say this,.. imagine that ravine,, it has no name back in 1855, right? so previous history, a teacher fell in that ravine and so people in the town probably would refer to it as "the Ravine miss Clayton fell in" eventually over time, people just call it "Clayton Ravine" there was probably no official ceremony or naming of geographical features.. so in the alternate time line,, people saw the train crash, they heard that clint eastwod died in that crash, so people would refer to that ravine as the place where clint eastwood died.. and eventually people just abbreviated it as "eastwood ravine"

It's the stuff legends are made of. The original Indian name of the ravine remained in tact because Clara was saved by Doc. She apparently had no immediate family and because her death was supposed to happen, she had no future. Thus making her a blank slate for whatever was to come.

As for the Eastwood Ravine... Marty aka Clint Eastwood had just saved Hill Valley from Mad Dog and his gang and for whatever reason went off to hijack a train. This must have been truly odd in the eyes of the townsfolk.

I'm sure that Doc Brown had to do a lot with the "legend" that was created afterwards. Upon returning to his blacksmith shop he would have to explain Clint's disappearance in correlation with the train wreck.

Of course the ravine would not be immediately named. But people talk and add their own versions to the legend, probably making it greater than it seemed. Probably people seeing "the ghost of Eastwood" a few times as well.

Thus people would petition to have it named Eastwood Ravine.

It was named just to honor the person. First for Clara, because she was willing to come out to Hill Valley alone (a big deal for women in the 1800's), and be the sole school teacher for an entire town. She died on the journey, so they named it after her out of respect. The fact that she may have been the first known case of a white person dying in it may have played a part as well (since 'Indians and Chinamen' and I'm assuming Blacks didn't count at the time).

Why it was named after Clint Eastwood, was to honor him as well. He apparently was the only person to ever stand up to Buford and live. He put on a great show in defeating him, and he helped save Hill Valley from the scourge that was the entire Tannen Gang. I don't buy into the theory about him being associated with the train hijackers. I mean, what legacy would that be? In the course of 1 hour he became the town's biggest celebrity. Hijack a train, not steal a single cent, keep everyone safe by disconnecting the cars, and then drive the train off a cliff killing yourself. I seriously doubt people would think of him going from the town's biggest hero to the town's biggest psycho all before 9am in the morning.

Um...maybe the same day Mad dog Tannon is taken out by Eastwood and a train going over a ravine was a memorable day for 1895 Hill Valley! Seems reasonable to name the ravine after the town hero-Clint Eastwood. It makes perfect sense.

Doc's long silvery hair is visible, despite the bandana he wore, and a whole trainload of people from the rest of the 'borrowed' train can be seen watching Doc and Marty going away in the locomotive. So there would be people who could put 2 and 2 together and know that Doc went in a train towards the ravine.