The advance of the frontier in Latin America has occurred in association with the predominance of large landholdings (latifundia) and oligarchic societies. In spite of the existence of free land, one of the fundamental premises of Turner's frontier thesis, in countries such as Brazil and Argentina, is that the concentration of land ownership has been one of the most permanent characteristics of the moving frontier. The main causes that explain this particular historical feature are: the colonial heritage and the Nineteenth century land laws. In this article we shall try to bring into focus some of the central aspects of the Portuguese and Spanish heritage, particularly in the field of territorial administration. We shall also examine the Br...