This chapter builds on recent scholarship uncovering the ways in which, just as there are modernisms, there are also regionalisms, and the two terms are not flipsides of the modernity coin but the same “side” of its Möbius strip, oscillating between op-position and co-position. More specifically, it focuses on the ways modernist debates over new versions of “culture” reshaped regionalism. New versions of “cultural pluralism,” arising out of interdisciplinary conversations among artists, anthropologists, geographers, and critics, were deployed in opposition to the homogenized, industrial nation-state. In these arguments, deployed by figures such as Randolph Bourne, Horace Kallen, and Edward Sapir, the unit of culture is both local and transnational, arising from the past but crucially oriented toward the future. These intertwined arguments of cultures, regions, and literary form are shared across key “communities of cultural interest” in the period, in particular the Southwest of Mary Austin and Native writers such as John Joseph Matthews and D’Arcy McNickle, and the South(s) of John Crowe Ransom and Zora Neale Hurston.