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Chaco Armistice – June 12, 2025

Chaco Armistice is a public holiday observed in Paraguay every June 12 to commemorate the end of the Chaco War between Paraguay and Bolivia. It is also called Chaco Peace Day and ‘Día de la Paz del Chaco’ in Spanish and is a solemn day of remembrance of the bitter war that occurred in the 1930s.

The parades celebrate the brave soldiers who sacrificed their lives for their country, but it is also a day to remember the loss of life and resolution to seek peace with Bolivia and other neighbors.

History of Chaco Armistice

The Gran Chaco is a wide, lowland, South American plain located in parts of Brazil, Bolivia, Paraguay, and Argentina. The area was deemed to have strategic value to both Paraguay and Bolivia because it granted access to the Atlantic via the Paraguay River. The region was also rich in natural resources, and it was thought to be rich in oil. Because of these factors, minor squabbles started happening between oil giants in both countries in 1928. Eventually, a full-out war erupted between Paraguay and Bolivia over control of the area in 1932.

Bolivia boasted superior numbers during the war, but they were unable to overcome Paraguayan guerrilla tactics. The latter was also supported by the French and Italian armies. The war waged for three years before the two parties signed a ceasefire agreement on June 12, 1935. As a result of this conflict, three-quarters of the Chaco region was given to Paraguay, with Bolivia getting navigation rights of the Paraguay and Parana Rivers and the remaining quarter of the territory bordering Puerto Busch. In addition, Bolivia lost around 60,000 people, or about 2% of its entire population, while Paraguay lost about 36,000.

Thus, the Chaco Armistice Day is held in honor of the 100,000 casualties of the war. To this day, the Chaco War is considered among the bloodiest military conflicts waged between two countries during the 20th century, making the victory bittersweet.

Chaco Armistice timeline


Minor encounters begin between oil companies in the two countries.

The War Erupts

A full-fledged war between Paraguay and Bolivia starts in the Chaco region.


Both parties sign a ceasefire agreement on June 12.

The Final Treaty

A treaty designating 75% of the Chaco region to Paraguay is signed.

Chaco Armistice FAQs

Why did Bolivia lose the Chaco War?

A number of reasons, including strategic errors, poor intelligence, and logistical problems in reaching distant battle lines, contributed to the losses on Bolivia’s side. Along with this, the morale of the Bolivian troops was low, and the highland Indians could not adapt to the extreme climate in Chaco’s low-lying region.

Who started the Chaco war?

The origins can be attributed to a long-standing territorial dispute and the discovery of oil deposits in the eastern Andes range. It was worsened by oil giants jockeying for exploration and drilling rights, with Royal Dutch Shell supporting Paraguay and Standard Oil backing Bolivia.

Why was the Chaco war important?

It is historically significant because it was the first instance of large-scale aerial warfare in the Americas. Both parties used obsolete, single-engined biplane fighter-bombers. While the Paraguayans used 14 Potez 25s, the Bolivians deployed at least 20 CW-14 Ospreys.

How to Observe Chaco Armistice

  1. Attend a parade

    Visit Paraguay and attend a parade in honor of the country’s war victory over Bolivia. It is also a public holiday, with many schools and offices closing for the day.

  2. Honor the dead

    Take a moment to honor the one million people who lost their lives during the war. Remember the fallen and victims and reflect on the conflict’s consequences.

  3. Raise awareness

    Share information about the war and the resulting massive loss of life with your friends and family. Post your thoughts on social media and help raise awareness about it.

5 Facts About Paraguay You Didn’t Know

  1. It has the world’s largest water reserve

    The Guarani Aquifer underneath Paraguay, Uruguay, Brazil, and Argentina is a vital source of fresh water.

  2. It’s a bilingual nation

    Most Paraguayans speak two languages: Guaraní and Spanish.

  3. Duels are still legal

    Duels are still legal in Paraguay, but you must be a registered blood donor to participate, and a professional medic must be on hand.

  4. The landlocked country has the largest navy

    The navy operates in Paraguay's rivers and can access the ocean through Argentina.

  5. It’s a wildlife paradise

    It’s home to the jaguar and over 1,000 bird species.

Why Chaco Armistice is Important

  1. It has a long history

    Although the war officially began in 1932, the territorial dispute had been around for a long time. The first confrontation between the two countries can be traced back to 1885, when Bolivian entrepreneur Miguel Suárez Araña established Puerto Pacheco, a port on the Upper Paraguay River.

  2. It honors the dead

    It’s important to take a day to remember the many people who lost their lives in the Chaco War and those who continue to be victimized by senseless wars today. The war resulted in countless deaths, but it has largely been forgotten by the English-speaking world.

  3. It wasn’t that long ago

    Although the war started a while ago, the treaty's details were only recently completed. A final document demarcating the border based on the 1938 border settlement was signed in Buenos Aires in 2009.

Chaco Armistice dates

2025June 12Thursday
2026June 12Friday
2027June 12Saturday
2028June 12Monday
2029June 12Tuesday

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