The American West is both a region — the lands beyond the Mississippi River that the United States conquered and settled across the nineteenth century — and a national myth about that region, built around the idea of the frontier as the force that shaped American character. This entry treats the West as an idea: the frontier thesis, the doctrine of manifest destiny, and the later scholarship that revised both.
In 1893 a young historian told a room of colleagues that everything distinctive about America — its democracy, its restlessness, its faith in the self-made man — had been forged on a single moving line: the frontier where settlement met open land. It was a thrilling story, and much of it was wrong. The land was not open. The line was largely a fiction of the census. Yet the idea proved almost impossible to kill. More than a century after scholars began taking it apart, Americans still reach for the frontier whenever they want to describe courage, reinvention, or a destiny worth chasing.