Uh, yes, I'd class Westerns as historical novels, especially when you are talking about the likes of Lonesome Dove by Larry McMurtrey, which I believe won a Pulitzer for best novel. Weird Westerns are starting to emerge as a blend of history and fantasy, but the old classic westerns written by Zane Grey and Louis L'Amour did stick to a fairly formulaic presentation. Zane Grey was pretty first in the genre, writing in the early 1900s, so he experienced at least the tail end of the authentic Old West to underpin his stories. There is no reason you can't write a really good Western as historical fiction, and I would say there is probably a pretty good market out there, especially among all us old fogies who grew up watching Saturday morning westerns as kids. There is also a certain nostalgia for what seems like more straightforward times, when the dangers were clear-cut and the solutions were (supposedly) equally clear. Bang! No more bad guy. It was never that simple, but we'd like to believe it was.
Long ago I read a terrific book called "Dead Warrior" by John Myers Myers, which was the story of a western boom town from the accidental discovery of gold to its evolution into respectability. It was excellent and I highly recommend it if you can find it.
