Roughing It covers an immense amount of geographical space. While it principally concerns the West and Pacific Coast, it also dips into the Hawaiian islands. Although Hawaii is still a sovereign nation at the time of Twain’s visit, it would eventually be incorporated into the United States, and its position at the close of this narrative presents it as the logical endpoint of westward expansion. In the mid-19th century, many Americans saw the West through the lens of frontier mythology, as a place of limitless possibility and danger. The extremes of the western landscape, with its immense mountains and hostile deserts, stood as a synecdoche for the romanticized ideals of adventure and self-invention that attached to the mythologized frontier. In his travelogue, Twain both punctures and embellishes these romanticized notions of landscape.

While Twain is primarily known as a humor writer, he also offers physical description of the various places he visits, and his impressions reflect attitudes that were common among 19th-century easterners exploring the American West for the first time. He is impressed by the sublime grandeur of the Rocky Mountains and the health-giving atmosphere surrounding Lake Tahoe, repulsed by the harsh deserts of the Great Basin, and skeptical of the dubious claims made by land-speculating boosters like newspaper magnate Horace Greeley.