1 Peso

Banco del Sur was a regional Colombian bank operating out of Pasto, the administrative center of Nariño department in the southwest of the country, geographically and commercially closer to Quito than to Bogotá. Its notes were issued under the framework of Colombia's free banking period, which persisted until the Banco de la República was established in 1923 and ended the circulation rights of private departmental banks.

The American Bank Note Company contract for this series is consistent with ABNC's dominant position supplying Colombian provincial banks during this period. The Pasto location meant these notes circulated in a frontier economy where counterfeiting pressure was low but redemption infrastructure was thin.