Bernard DeVoto 
The Year Of Decision, 1846 [EPUB ebook] 

This book tells the story of some people who went west in 1846.
Its purpose is to tell that story in such a way that the reader may realize the far western frontier experience, which is part of our cultural inheritance, as personal experience. But 1846 is chosen rather than other years because 1846 best dramatizes personal experience as national experience. Most of our characters are ordinary people, the unremarkable commoners of the young democracy. Their story, however, is a part of a decisive turn in the history of the United States.