As the mother French possession in Africa, Senegal was always considered as an old colony and this has created the impression that its formation as a politico-territorial unit was not so much the result of the scramble for Africa or yet did not really depend on the coloniser's discretion. Now that present-day Senegal has existed for 70 years, it could be tempting to conclude from this impression that this colony was merely super-imposed on a field of historico-social forces where a nation was in gestation. However, such an assumption would be much too conjectural. First the original heterogeneity of the population seems to impair this view. Secondly, the evolution of Senegal as a colony suggests clearly that it was tied to external decisions and actions and to issues which went far beyond it. Thirdly, French rule in Senegal shows that the coloniser, who did not consider traditional cultural and political distributions, has had a decisive influence on the formation of Senegal as a political territorical unit.