Religious persecution, segregation, and commercial networks triggered the diaspora of Iberian New Christians and Sephardic Jews throughout the Atlantic in the Early Modern period. Despite the geographical dispersion, the diverse host environments, and the complex religious experiences, the so-called Western Sephardic Diaspora was founded on the principles of unity and preservation, which were cemented by the notion of belonging to the Nação. Thus, as a cross-border community connected by common geographical origins, collective cultural identity, and a shared New Christian background, the concept of Nação was structural for the definition and evolution of the diasporic experience of Portuguese and Spanish exiles and their descendants from the sixteenth to the eighteenth centuries. This article overviews the most recent findings and perspectives on the concept of the Nação as a unifying element of the Western Sephardic Diaspora. Then, it problematizes the interpretation of this concept in different Sephardic communities established in Atlantic port cities. This problem is approached by analyzing these communities’ internal bylaws (ascamot) under the lens of two critical questions: (1) the concept of Nação as defining the borders of belonging to the community and (2) the unity and preservation of the Nação as essential drifts of the organization and management of the community. This analysis emphasizes the tension between the dynamism and particularities of each community and the conservatism of the idea of Nação, promoted by small social and economic elites that exercised increasing control over the communities and their interaction with the surrounding environments.