1 Real Fuerte

The Banco Entre-Riano operated out of Concepción del Uruguay, the then-capital of Entre Ríos province, during a period when Argentine provincial banking was essentially unregulated. Provincial banks of this era issued their own notes with little federal oversight — the national banking law that would begin consolidating currency authority didn't arrive until 1872. Notes printed locally in the provinces, rather than contracted to British or American security printers, are considerably rarer survivors; provincial print shops lacked the paper stock and anti-counterfeiting infrastructure of the major houses.

PS prefix in the Pick system flags this as a private and local issue, and PS1657 is sparsely documented.