The purpose of this paper is to enrich the analytical record of the process of formation of the political system of the Argentine “Confederation” in the 1850s, from the specificities of San Juan province. We considered variations of San Juan political and economic integration in the national and “transcordillerano” stage. We reveal that the attempts of San Juan authorities to (re)articulated in a long-standing activity as overland trade with Chile, though not always successful, were important both to define provincial political tensions and the gravitation of the province in the political and institutional frame of the “Confederation”. So, we analyzed provincial, regional and international aspects of this process, taking into account the multiplicity of actors, resources, ideas and practices that were involved. [ABSTRACT FROM AUTHOR]