1 Peseta Castejón de Sos

Castejón de Sos is a small mountain municipality in the Aragonese Pyrenees, and like hundreds of Spanish towns during the Civil War, it issued its own emergency paper currency when the Republic's central supply of small change collapsed entirely. These local issues — called billetes de necesidad or war money — proliferated from 1936 onward as hoarding and metal requisitioning stripped coins from circulation. The issuing authority here, a Municipal Economic Council, was the standard administrative body established in Republican-held territory to manage local economic functions under wartime conditions.

The official seal is the sole security feature, which was typical of the more remote municipal issues where printing resources were whatever the local council could arrange.