This dissertation examines literary articulations of national identity from the 1820s to the 1920s and finds that the qualities that purportedly define the national literature of the United States (“American literature”) and the qualities that purportedly define the regional literature of the American West (“Western literature”) frequently become conflated and entangled. When American writers attempt to produce texts that articulate the national character, the West is an indispensable source of images and virtues. But at the same time, they also turn to the West when they need to estrange undesirable characteristics. This pattern of making the West the same but different, the essence and also the other of the nation, I argue, produces and reproduces this eponymous paradox: at the same time that only a subset of American literature is Western, all of it is. Although the precise terms under which the nation and the region are defined change over the period I discuss in “West of What?”, I nonetheless show how examining the West’s special relationship to the nation produces literary histories of American literature that expose surprising, counterintuitive narratives of many crucial themes, including transnationalism, gender, boosterism, and nativism.,The dissertation’s four chapters are arranged chronologically, beginning with the twin births of Western and American literature in the late 1820s. The first chapter, “Alternative Transnationalisms: Timothy Flint and the Atlantic Reviewers,” argues that Flint produces defiantly Western writing that actually constitutes a reimagining of American literary transnationalism. I show how Western regionalism complicates our understanding of how the idea of American literature fits into hemispheric flows of people, ideas, and texts by acting as an alternative to rather than merely a subset of the national literature. It uses new evidence published in Flint’s Western Monthly Review to show that his novel Francis Berrian (1826) is as concerned with sectional rivalries as it is with international ones. The second chapter, “Frontier Manliness: Francis Parkman, Jr., the West, and The Knickerbocker,” inverts how cultural historians have long understood the relationship between manliness and the Western frontier in the 1850s by arguing that Francis Parkman, Jr.’s iconic travel narrative The Oregon Trail (published serially 1847-1849) produces a version of Western manliness characterized by aesthetic vision rather than violence. In my reading, The Oregon Trail becomes not a wellspring of a revitalized national manliness, but rather a reinscription of the forms of gender performance that it claims to transcend. The third chapter, “Fiction and Authenticity: Boosterist Periodical Fiction at the Closing of the Frontier,” examines a corpus of texts published in Western periodicals that are avowedly boosterist. Their ostensible strategy is to show how the West is different from the nation because it is romantic and exciting and part of the nation, which makes it a safe place for investment, and then to present this paradox in writing that audiences will interpret as authentic. But I show how these texts undermine their own commercial projects in surprising ways, deploying irony and self-awareness in their self-sabotage. The fourth chapter, “Americy to America: Multiculturalism and Nativism in Willa Cather,” restructures the relationship between regionalism and transnational modernism in the career of Willa Cather by showing how even Cather, perhaps the writer most closely associated with Western literary regionalism to achieve widespread literary recognition, is unable to produce a cogent differentiation of Western from national literary qualities. I argue that Cather’s prairie novels, especially One of Ours (1922), express her ardent desire to offer an account of a distinctively Western embrace of European immigrants, even as maintaining Randolph Bourne’s ideal of a transnational America proves to be impossible as the West becomes swallowed up by the nation in a surge of national feeling associated with the nation’s entrance into WWI.