Cisplatina was a Brazilian province in existence from 1821 to 1828 created by the Luso-Brazilian invasion of the Banda Oriental. Wikipedia

Former province of Brazil Wikidata

The former Cisplatina Province or Cisplatine Province (Província Cisplatina), a province on this side of the River Plate (from the Brazilian perspective); it existed in the 1820s and was a focus of the Cisplatine War but then became part of what is now Uruguay. Wiktionary