50 Pesos El Estado de Sonora

Sonora's state government issued its own currency during the Mexican Revolution because the federal monetary system had effectively collapsed — competing factions controlled different regions, and Constitutionalist-aligned Sonora needed a functioning medium of exchange independent of Mexico City. The American Bank Note Company contract reflects both the financial sophistication of the Sonora government and the practical impossibility of commissioning quality security printing domestically during active conflict.

The S1075 series is relatively available compared to many Mexican revolutionary issues, but circulated examples showing heavy fold wear are common — these notes moved through commerce in a border economy that included Arizona trade crossings.