America’s racial and cultural identity was contested and in flux at the turn of the twentieth century as millions of ethnic immigrants arrived in the United States. While many Americans embraced the idea of the nation as a “melting pot,” countless others feared that the new arrivals posed a threat to the nation’s future; they maintained that white Americans had founded the nation and were therefore its rightful heirs. In that moment, concerned Americans turned their attention to the mountain whites of southern Appalachia– a people who were generally disdained for their social and cultural difference from mainstream Americans, but also considered laudable for their racial purity, native-American birth, and latent potential. Reclaiming Appalachia traces those late-nineteenth and early-twentieth century efforts to salvage and incorporate Appalachian whites living in the mountain areas of Kentucky, Tennessee, Virginia, North and South Carolina, Georgia, and Alabama into the mainstream American social and political fold. It shows that interventionists’ views regarding mountain whites’ racial worth and essential Americanism ran the gamut from white nationalism and white supremacy to a latent anti-modernist concern for preserving a disappearing “authentic” rural American people and experience. Despite their diverse and sometimes overlapping perspectives, interventionists collectively understood their efforts as vitally important to the future of American culture and democracy. By presenting that process as part of the burgeoning Americanization movement, this dissertation reveals that mountain uplift was a crucial component of efforts to cultivate citizenship and cultural homogeneity across the nation, and demonstrates that regional reform was as much about changing the mountain interior as it was about solidifying the nation’s racial and civic identity. Most importantly, it illuminates the central role that rural white Appalachians played in the formation and re-formation of early-twentieth century Americans’ ideas about the relationship between race, citizenship, and Americanism.