The dynamics of an administrative geography, the sous-prefecture and canton network in the 19th and 20th centuries in the Nord and Pas-de-Calais

After a reminder of the foundation period (1789-1800) with the debates, the stakes and the reasons of the new administrative structure, this paper sig nals the major alterations that took place at arrondissement level-creation of the arrondissements of Valenciennes(1824), Calais and Lens (1962), disp arition of those of Hazebrouck and Saint-Pol-sur-Ternoise (1926)-, and at c anton level with the creation of new ones and the splitting of older ones, all of them situated in densely populated, harbour or industrial areas. The n it studies the action of the various local lobbies as well as the interve ntions of the region's MP's about the administrative grid of the Nord and P as-de-Calais or about the global plan of eliminating the sous-prefectures o r regarding decentralization. Finally, it raises the question of the perenn iality of this grid whose relevance is questioned by the development of new territories like the communities of communes, the urban districts or the c ountries.