This chapter discusses how separate nation-states crystallized, turning Latin America into a multistate region subject to persistent transnational trends. The story of Latin America as a multistate region is one of contested territorial boundaries and a tension-ridden consolidation of separate collective identities out of a tapestry of transnational interaction. The chapter traces how states were constructed and narrated national formation; how transnational visions continued to reverberate; how transnational events such as wars were framed as national; and how transnational social movements promoted interstate connections, sometimes trying to recreate the lost unity of earlier times and the transnational visions of some of the founding fathers of independence. The textual discussion addresses cases of the Southern Andean and Río de la Plata expanses, namely Bolivia, Ecuador, Peru, Uruguay, and Brazil, as well as Central America, including primarily El Salvador, Guatemala, Honduras, Nicaragua, and Costa Rica. The chapter also embeds references to the Latin American countries.