This work is the result of research that began as part of a Master's Degree project at the Fluminense Federal University, which set out to study the city of Barra Mansa in its territorial configuration. In order to do this, its origins in the occupation of the Paraíba Fluminense Valley were researched. The first penetrations and roads gave Barra Mansa its centrality. We sought to identify its economic cycles, from the first farms to industrialization, outlining its history and occupation, highlighting the importance of this point of convergence of roads and also of political and economic interests. We tried to understand the rapid and disorderly occupation induced by industrialization. We studied the importance of the convergence of the unique roads and then the railways that provided the conditions for industrialization and its consequences and marked its territory. The main concern of this work was to highlight and study the importance of railroad and industrial development in the process of occupation and territorial articulation of the Sul Fluminense region, especially Barra Mansa.