100 Colones 150 Años de Independencia

Issued to mark the sesquicentennial of Central American independence from Spain — declared on 15 September 1821 — this is one of the few commemorative notes Costa Rica produced in the twentieth century. Thomas De La Rue handled the printing, as they did for the majority of Banco Central issues from this period, a relationship that dates back well before the Central Bank's 1950 founding to earlier concession-era notes printed for Costa Rica's private banks.

The format is notably square by any measure — 167 by 156 mm puts it close to a 1:1 aspect ratio, which is genuinely unusual for a circulating banknote of this denomination.