This painting shows Manifest Destiny, the belief in westward expansion of the United States from the Atlantic to the Pacific Ocean. It was widely distributed as an engraving called "Spirit of the Frontier". Settlers are moving west, guided and protected by Columbia, aided by modern technology like railroads, and driving Native Americans and bison into obscurity. Columbia represents America, dressed in a Roman toga to represent classical republicanism, and brings the enlightened east to the darkened west.
<bdi><a href="https://en.wikipedia.org/wiki/en:John_Gast_(painter)" class="extiw" title="w:en:John Gast (painter)"><span title="American artist (1842-1896)">John Gast</span></a>
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