Last day of the Battle of Boquerón between Paraguay and Bolivia during the Chaco War.

The Battle of Boquerón was fought September 7–29, 1932, between the Bolivian and Paraguayan armies in and around the stronghold of Boquerón. It was the first major battle of the Chaco War. The outpost (fortín) of Boquerón, among others, had been occupied by Bolivian troops since late July 1932 following instructions of president Daniel Salamanca, which led to the escalation of what began as a border conflict into a full-scale war. The Bolivian garrison was under the command of Colonel Manuel Marzana.

Paraguay, officially the Republic of Paraguay, is a landlocked country located in the central region of South America. It is a unitary state with a territory composed of a capital district and seventeen departments. Its capital and largest city is Asunción. Paraguay is a presidential republic and a state governed by the rule of law. It is a founding member of Mercosur, along with Argentina, Brazil and Uruguay.

Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, warm valleys, high-altitude Andean plateaus, and snow-capped peaks, encompassing a wide range of climates and biomes across its regions and cities. It includes part of the Pantanal, the largest tropical wetland in the world, along its eastern border. It is bordered by Brazil to the north and east, Paraguay to the southeast, Argentina to the south, Chile to the southwest, and Peru to the west. The seat of government is La Paz, which contains the executive, legislative, and electoral branches of government, while the constitutional capital is Sucre, the seat of the judiciary. The largest city and principal industrial center is Santa Cruz de la Sierra, located on the Llanos Orientales, a mostly flat region in the east of the country with a diverse non-Andean culture.