To possess and develop western North America became a high priority for the United States government even before its Constitution had been complete. For President Thomas Jefferson, the vast terrain of plains, mountains, and extensive coastlines offered both long-term prosperity and protection from competing international powers. 

Railroads were still some decades off, and passable roads were all but nonexistent. From its first interactions with numerous Indian cultures, the government understood that the western portion of the continent was already "owned" by a variety of indigenous tribes, despite their alternate concept of ownership. To gain possession of the coasts and the interior meant there would be new languages to be learned, hundreds of treaties to be struck, and wars to be fought over several regions. No familiar institutions of power were suitable for creating a foothold in the continent's interior, especially in the Rocky Mountain region. The US Army eventually made inroads to the Great Plains and beyond, but the first true explorers of the far west’s interior arose from within a relatively small culture embodied by the American mountain man.

By the golden age of the mountain man in the mid-19th-century, there were perhaps only 3,000 living in the West. Their origins were disparate, although they included many Anglo-Americans. A good number hailed from wilderness regions of Kentucky and Virginia and throughout the newly purchased Louisiana Territory, which occupied the entire central section of the continent. French Canadians traveled from the north to work in the fur trade, while Creole-Europeans represented approximately 15% of the men known to be living the isolated mountain life.

Although the most enduring accomplishments belonged to the mountain men who had discovered, charted, and helped build the great passes through the Rockies to the west, others have retained public fascination for simply being colorful and elusive historical personalities. Such was the case of a legend who came to be known by the singularly unappetizing moniker of Liver-Eating Johnson. One of the mountain men who was present from the peak of mountain culture to its twilight, his literal accomplishments are few and of limited scope in the sense of exploration; however, he is intimately associated with a dangerous life of intrigue, revenge, and physical horrors unspeakable in polite society. While his colleagues took steps to tame the American wilderness, he became a symbol of its savagery. Johnson’s protracted war of vengeance speaks of a constant interaction with the Crow culture of the northwest and the territories of Wyoming and Montana in particular.