War of the Pacific: The Conflict Between Chile, Bolivia, and Peru

The War of the Pacific (1879–1884) was a defining geopolitical struggle in South America, pitting Chile against the allied forces of Bolivia and Peru. Fought primarily over the resource-rich Atacama Desert, the conflict reshaped the borders of three nations and left a lasting legacy of territorial disputes and national identity.

At its core, the war was driven by the economic value of nitrate (saltpeter) and guano, which were essential for fertilizer and gunpowder. The struggle for control over these deposits transformed a regional border dispute into a full-scale military campaign involving naval battles and grueling land warfare.

The Atacama Desert border dispute between Bolivia and Chile (1825–1879)

Key Facts

Duration: March 1, 1879, to April 4, 1884.
Belligerents: Chile vs. Bolivia and Peru.
Primary Cause: Disputes over nitrate deposits and a 10-cent tax imposed by Bolivia.
Outcome: Chilean victory; Bolivia lost its coastline, and Peru ceded southern territories.
Major Treaties: Treaty of Ancón (Chile-Peru) and Pact of Valparaiso (Chile-Bolivia).

The Roots of Conflict

Flow of news during the War. Distances in kilometers are great-circle distance, for land and sea routes.

Border Disputes and Secret Alliances

The tension began with ambiguous borders in the Atacama Desert. While a 1793 map showed certain boundaries within the Spanish Empire, the independent republics struggled to agree on limits. A 1866 Boundary Treaty attempted to resolve this, but tensions remained.

1793 Map of Andrés Baleato showing Peru and Chile's border inside the Spanish Empire.

In 1873, Peru and Bolivia entered into a Secret Treaty of Alliance. This pact was designed as a mutual defense agreement, though Chile only learned of its existence through leaks in the Argentine Congress. Meanwhile, a 1874 Boundary Treaty between Chile and Bolivia explicitly forbade tax increases on Chilean enterprises for 25 years.

The "Ten Cents" Crisis

The spark for the war was economic. Peru sought to monopolize nitrate works to stabilize its economy, which was suffering from a decline in guano exports. In 1878, Bolivia approved a tax of 10 cents per quintal on nitrate exports. Chilean companies, citing the 1874 treaty, refused to pay, prompting the Chilean government to intervene and eventually invade Antofagasta.

Military Capabilities and Technology

None of the three nations were fully prepared for a prolonged conflict. They lacked formal General Staffs, medical corps, and robust logistics. However, Chile possessed a more modernized military structure and better-equipped forces.

Technological shifts played a role in the fighting. The transition from paper cartridges, which produced smoke and ash, to metallic brass cartridges (such as those for the Fusil Gras mle 1874) improved efficiency and visibility on the battlefield.

A metallic brass cartridge for a Fusil Gras mle 1874 and a paper cartridge for a Chassepot rifle. The brass cartridge avoided the smoke and ashes of the self-consuming paper cartridge.

The Course of the War

The Struggle for the Sea

Control of the Pacific coast was vital for transporting troops and supplies. The naval campaign saw intense clashes, including the Battle of Iquique, as Chile sought to neutralize the Peruvian Navy's ironclads to secure landing zones for its army.

Land Campaigns

The war progressed through several brutal phases:

Tarapacá Campaign: Chilean and Allied troops deployed in November 1879, leading to the Battle of Tarapacá.
Tacna and Arica: From January to June 1880, fighting intensified in these regions, resulting in significant casualties.
Campaign of Lima: Chilean forces landed at Pisco and Chilca, eventually engaging in the devastating Battles of Chorrillos and Miraflores.

Landing and deployment of Chilean and Allied troops during the Campaign of Tarapacá, in November 1879.

Landing and deployment of Chilean and Allied troops during the Campaign of Tacna and Arica from January to June 1880.

Landing and deployment of Chilean troops during the Campaign of Lima, from November 1880 to January 1881. The long way from Pisco to Chilca was done only by the Lynch brigade.

The Battle of Chorrillos was particularly destructive; the seaside resort, once a haven for Lima's aristocracy, was reduced to rubble during the fighting.

Chorrillos was the preferred seaside resort of Lima's aristocracy before the war, but during the Battle of Chorrillos, the Peruvian line of defense ran in the middle of the city and was shelled, set on fire, looted, and reduced to rubble during the conflict. At the end of the battle, bitter fighting had raged in every ruin and street.

Chorrillos, and the consequences of the war. January 1881

The Sierra Campaign

Following the fall of Lima, the conflict shifted to the Peruvian highlands (the Sierra). This phase was characterized by guerrilla warfare and harsh conditions. Soldiers faced not only combat but also diseases like Carrion's disease, known as the "Peruvian wart."

A Chilean soldier with the "Peruvian wart," or Carrion's disease, who was probably infected in the valleys of the Rimac River during the war in the sierra.[164]

Human Cost and Atrocities

The war was marked by significant human suffering. Approximately 25,000 soldiers were killed. In Chile, 4,081 soldiers (10% of the expeditionary force) returned disabled. The conflict also saw the expulsion of 30,000 Chileans from Peru and Bolivia at the start of the war, many of whom later joined the Chilean army.

Chilean lieutenant Solo Zaldívar and two soldiers burying three Bolivian soldiers after the Battle of Tacna. The elevation behind them is also a burial ground of victims.

Martiniano Urriola, with kepi, the commander of the occupation of Ayacucho in 1883, and Marcos Maturana, with poncho, the general chief of staff chief of the Expeditionary Army during the Lima Campaign; they view the dead bodies of a Peruvian gun crew after the Battle of Chorrillos.

Photo of Chilean private first class Tránsito Diaz, injured during the landing on Pisagua. The photo belongs to the "Álbum de inválidos de la Guerra del Pacífico", 130 photographic records ordered by the D. Santa María government to demonstrate the pensions and orthopedic devices given to disabled war veterans.[126] Ten percent of the expeditionary force, 4,081 Chilean soldiers, returned disabled from the war. In 2008, 280 women were receiving a pension as the daughter or wife of a veteran.[127]: 20, 30

Human remains of Bolivian, Chilean and Peruvian soldiers exhumed from makeshift graves after the Battle of Tacna before their definitive interment in the Mausoleum of the Tacna cemetery in 1910.[186]

Mural commemorating six Peruvians executed by firing squad in Quequeña.

Peace and Aftermath

The war ended with the Treaty of Ancón (1883) between Chile and Peru, and the Pact of Valparaiso (1884) between Chile and Bolivia. The territorial changes were profound:

Territorial and Political Outcomes of the War of the Pacific
Nation	Outcome	Territorial Change
Chile	Victory	Acquired Antofagasta (from Bolivia) and Tarapacá (from Peru).
Bolivia	Defeat	Lost its entire coastline (Litoral), becoming landlocked.
Peru	Defeat	Ceded Tarapacá; Arica was later ceded in 1929, while Tacna was returned.

To ensure Argentine neutrality during the conflict, Chile dropped claims to over 1,000,000 km² of Patagonia in an 1881 treaty.

Caricature in the Chilean magazine Padre Cobos. Minister Balmaceda washes his hands of responsibility and orders Intendent of Santiago Benjamín Vicuña Mackenna to get rid of the heavy Peruvian lion. The Santiago elite observes with pleasure the arrival of the statue. "Padre Cobos" and a black child play around.

Statue in Bolivia of Eduardo Abaroa pointing to the sea.

Frequently Asked Questions

What was the primary cause of the War of the Pacific?

The war was primarily caused by disputes over the ownership and taxation of nitrate (saltpeter) deposits in the Atacama Desert, specifically triggered by Bolivia's imposition of a 10-cent tax on Chilean nitrate companies.

How did the war affect Bolivia's geography?

Bolivia suffered the most significant geographical loss, losing its entire coastal territory to Chile, which rendered the country landlocked.

What was the significance of the Treaty of Ancón?

The Treaty of Ancón ended the war between Chile and Peru in 1883, resulting in Peru ceding the province of Tarapacá to Chile and establishing a long-term dispute over Tacna and Arica.

Who won the War of the Pacific?

Chile emerged as the victor, successfully seizing nitrate-rich territories from both Bolivia and Peru and establishing dominance over the southeastern Pacific coast.

What was the "Peruvian wart" mentioned in historical records?

The "Peruvian wart" refers to Carrion's disease, an infection that affected soldiers, particularly during the Sierra Campaign in the valleys of the Rimac River.