` ::Thanks for the info. However I think there is still a real question here. I believe your evidence that ``Mount Lassen`` is the most common local name of the mountain, where ``local`` means people who live nearby. However that does not make it necessarily the most common name of the mountain among all English speakers. (In looking at the intent of the relevant guideline, I think that is what is key, but I could be wrong.) In fact, I would say that easily the more common name among all English speakers (or even all Americans) is Lassen Peak. It is the name that is more commonly used in published literature about the mountain (by a large factor, AFAIK), so this is how most Americans know it. Added to that is the fact that it is the official name, which I do think counts for something.  ::An example: suppose that everyone living near a mountain calls it by a local nickname, but visitors from elsewhere, guidebooks, state and federal descriptions, all call it by a different name. Using the local nickname as the article title would be inappropriate, since the vast majority of people looking at Wikipedia would not be familiar with that name. I don't want to disparage the ``Mount Lassen`` appellation as just a nickname, but it seems to me to be a similar case. However, I admit it does seem strange in some ways not to use a common local name. ::I would suggest waiting a few days to see if there is more input on this question before doing any more moving around, to avoid unnecessary edits/reverts.   `