The Primera Junta, the first independent government in Argentina, was established in an open cabildo in Buenos Aires, marking the end of the May Revolution.

The Primera Junta or Junta Provisional Gubernativa de las Provincias del Río de la Plata, is the most common name given to the first government of what would eventually become Argentina. It was formed on 25 May 1810, as a result of the events of the May Revolution. The Junta initially only had representatives from Buenos Aires. When it was expanded, as expected, with the addition of representatives from the other cities of the Viceroyalty of the Río de la Plata, it became popularly known instead as the Junta Grande or Junta Provisional Gubernativa de Buenos Aires. The Junta operated at El Fuerte, which had been used since 1776 as a residence by the viceroys.

The open cabildo is a traditional Hispanic American political assembly for convening citizens to deliberate policy. Originating in Spanish America as an iteration of the cabildo, it also spread to Spain.

Buenos Aires, controlled by the government of the Autonomous City of Buenos Aires, is the capital and largest city of Argentina. It is located on the southwest of the Río de la Plata. Buenos Aires is classified as an Alpha− global city, according to the GaWC 2024 ranking. The city proper has a population of 3.1 million and its urban area 16.7 million, making it the twentieth largest metropolitan area in the world.

The May Revolution was a week-long series of events that took place from 18 to 25 May 1810, in Buenos Aires, capital of the Viceroyalty of the Río de la Plata. This Spanish colony included roughly the territories of present-day Argentina, Bolivia, Paraguay, Uruguay, and parts of Brazil. The result was the removal of Viceroy Baltasar Hidalgo de Cisneros and the establishment of a local government, the Primera Junta, on 25 May.