I suggest in this contribution to study the history of childhood and adolescence in Alsace, a region located at the crossroad of Europe, which is between France and Germany. More specifically, I concentrate on the youth organizations that support young Alsatian people outside of school hours. European historians agree to call them “youth movements”. My purpose here is not to reduce the diversity of youth movements, but to seek to go beyond it, as in the approach taken by the French historian Aline Coutrot. Given the vicissitudes of Alsatian political history, it would indeed seem that local movements tend to encourage their convergence, in order to assert their role as actors in the defence of French interests and/or Alsatian characteristics. This very question can be addressed from different points of view, such as interreligious relationships, or relationships between private initiatives and public policy, or the region/nation dialectic. It is these third issue which is particularly interesting here. Within the Alsatian context of the early twentieth century, the very sensitive theme of nationality permeates the youth movements.