Background: The Tacna–Arica space (Tacna, Peru, and Arica, Chile) was historically a territory of intense Afro-descendant presence that, following the War of the Pacific and the Treaty of Lima (1929), suffered a political fragmentation of its genealogical and cultural networks, which is today sparsely documented. This study aimed to describe and analyze the most significant genealogies and legacies of Afro-descendant culture in this space, reconstructing transborder historical memory. Methods: A qualitative approach with an oral history ethnography design was adopted, using purposive and snowball sampling. Nine in-depth interviews were conducted with key informants from the Sama Valley (Tacna) and the Azapa Valley (Arica), which were analyzed using inductive–deductive thematic coding with ATLAS.ti software. Results: Four categories were identified: (1) historical memory and the trauma of transborder refuge; (2) identity and asymmetric legal gaps between both countries; (3) shared cultural expressions and popular religiosity; and (4) structural adversities of border rurality. Conclusions: Afro-descendant oral memory operates as a counter-narrative of resistance against official historiography, and popular religiosity constitutes the most resilient transborder link between Sama and Azapa, despite the legal asymmetries between Peru and Chile.