This dissertation examines interactions and circuits of exchange between Anglophone and Hispanophone literary cultures in the wake of the Mexican-American War, particularly those involving African-American, Indigenous, Latin American, and proto Latina/o-American communities. My dissertation grapples with the breadth of multilingual Americas, examining the stakes of U.S. territorial expansion and empire through a range of translations, adaptations, and literary borrowings that enabled the transit and transmutation of texts in the mid-nineteenth and early-twentieth centuries. I focus on works by a range of writers, poets, activists, politicians, and translators, including Carlos Morla Vicuña, John Rollin Ridge, Gabriel de la Concepción Valdés, José Martí, Helen Hunt Jackson, Martin Delany, and Willa Cather. I draw upon letters, periodicals, novels, and poems that circulated in the Americas, arguing that choices and practices of translation were in dialogue with shifting frameworks of race and ethnicity in these different contexts. My analysis of these textual forms depicts some of the distinct ways that authors employed translation as a mode of political activism. Ultimately, this dissertation examines the relation between translation and national belonging in these different contexts, unveiling the varied forms by which transgressive translation strategies were harnessed as forms of anti-imperialist work even as they often initiated or replicated neocolonial and imperialist practices.