In 1976, while performing an investigation similar to the one which served as a basis for the identification of administrative regions and subregions of Québec in 1965, a hierarchy of attraction poles was defined and their spheres of influence identified, for the administrative region of Trois-Rivières. The resulting comparison indicated very little change in the hierarchy, except for the emergence of three smaller towns at the lower level of the hierarchical structure. One notices a relative stability in the links between the rural municipalities and their urban attraction pole. The most important spatial changes relate to the regional capital's zone of influence, which intensified and spread into the southern portion of the region, following the construction, in 1967, of a permanent and toll-free road link with the south shore of the St. Lawrence. The evolution of the region's spatial polarization is confirmed by the choices made last year at the municipal level during the merger process leading to the creation of the area's ten regional municipalities.