This paper was written within the framework of a thesis project for the Master's Degree in Urban and Regional Planning at the University of Buenos Aires. It deals with a case study of Trenque Lauquen City (located in the northwest of Buenos Aires Province, Argentina**); it attempts to understand processes of territorial transformation experienced since the city was founded, in 1876. The "round lake", which gives its name to the city in the language of the Mapuche Indians, is surrounded by urbanization, and located within the sub-humid Pampa. According to the last census of population and housing, it hosted 30,764 of the 13,827,203 inhabitants of the province's territory in 2001. It concentrates the main regional economic activities: agriculture, dairy farming and cattle raising. Secondary and tertiary activities also take place there: manufacturing industry, services and commerce. Our research activities are aimed to studying the territorial organization and the places developed through the history of Trenque Lauquen. To that end we apply theoretic-methodological criteria for territorial analysis from the analysis guidelines of time-space, systems of objects and systems of actions.