War of the Pacific (1879-1884): Chile, Peru, Bolivia and Nitrate

The War of the Pacific (1879-1884) was fought between Chile on one side and Peru and Bolivia on the other for control of the Atacama Desert, whose nitrate and guano deposits were among the most valuable natural resources of the nineteenth century. Chile won decisively, occupying Lima and annexing the coastal provinces of its rivals. The war reshaped the map of South America, made Chile the dominant power of the Pacific coast and left Bolivia without access to the sea, an issue that still divides the countries today.

Background: nitrate in the desert

The Atacama, one of the driest places on Earth, held huge deposits of sodium nitrate, known as saltpeter, and of guano, both prized in Europe as fertiliser and, in the case of nitrate, for making explosives. The borders through the desert, inherited from Spanish colonial divisions, had never been clearly fixed.

Bolivia held the coastal province around Antofagasta, Peru the province of Tarapacá to the north. Much of the capital and labour working the deposits, however, was Chilean, often backed by British investors. An 1874 treaty set the Chile-Bolivia border at the 24th parallel and committed Bolivia not to raise taxes on Chilean companies operating there for 25 years.

Peru and Bolivia had also signed a secret defensive alliance in 1873. Peru, whose economy depended heavily on guano and which had nationalised its own nitrate works, was alarmed by Chile’s growing influence.

The ten cents tax

In 1878 the Bolivian government of President Hilarión Daza imposed a tax of 10 centavos per quintal of nitrate exported by the Antofagasta Nitrate and Railway Company, a Chilean-British firm. Chile insisted this broke the 1874 treaty. When the company refused to pay, Bolivia moved to seize and auction its property.

On 14 February 1879, the day of the planned auction, Chilean troops landed and occupied Antofagasta. Bolivia declared a state of war at the start of March. Peru attempted mediation, but Chile, learning of the secret alliance, declared war on both Peru and Bolivia on 5 April 1879.

The naval war

Control of the sea was decisive, because armies in the waterless desert could be supplied only by ship. On 21 May 1879, at the Battle of Iquique, the Peruvian ironclad Huáscar under Miguel Grau sank the old Chilean corvette Esmeralda; its commander, Arturo Prat, was killed leading a boarding attempt and became Chile’s greatest naval hero. The same day, however, the Peruvian ironclad Independencia ran aground while chasing a smaller Chilean ship and was lost.

For months the Huáscar raided Chilean shipping and ports, tying down the Chilean fleet. On 8 October 1879, at the Battle of Angamos, Chilean ironclads cornered and captured it. Grau was killed, and Chile gained command of the sea for the rest of the war.

The land campaigns

Chile landed at Pisagua on 2 November 1879 and won at San Francisco (Dolores) later that month, securing Tarapacá despite an allied victory at the Battle of Tarapacá on 27 November. The defeats brought down both allied presidents: Daza was overthrown in Bolivia, and Peru’s Mariano Ignacio Prado left for Europe, replaced by Nicolás de Piérola.

In 1880 the Chilean army, commanded by General Manuel Baquedano, won the Battle of Tacna (Alto de la Alianza) on 26 May, after which Bolivia effectively withdrew from the fighting. On 7 June Chilean troops stormed the fortified headland of Arica, where the Peruvian commander Francisco Bolognesi was killed.

Chile then struck at the Peruvian capital. After hard-fought victories at Chorrillos on 13 January 1881 and Miraflores on 15 January, Chilean forces entered Lima on 17 January 1881. The occupation lasted nearly three years.

Peruvian resistance continued in the Andes under Andrés Avelino Cáceres, whose guerrilla campaign in the highlands, known as the Breña campaign, inflicted losses such as at Concepción in July 1882. Cáceres was finally defeated at Huamachuco on 10 July 1883.

Peace treaties

The Treaty of Ancón, signed on 20 October 1883, ended the war between Chile and Peru. Peru ceded Tarapacá permanently; Tacna and Arica were to remain under Chilean control for ten years, followed by a plebiscite. Chilean troops left Lima soon afterwards, in October 1883, and withdrew from the rest of Peru in 1884.

Bolivia agreed only to the Truce of Valparaíso on 4 April 1884, which left its coastal province under Chilean administration. A final Treaty of Peace and Friendship in 1904 confirmed the cession, in return for Chilean payment and the construction of a railway from Arica to La Paz with guaranteed transit rights.

By the numbers

Consequences

For Chile, victory brought enormous wealth. Export taxes on nitrate funded the state for decades, financing railways, ports, schools and a strong military, although much of the industry came under British ownership. The boom ended after the First World War, when synthetic nitrate made in Germany undercut the natural product.

The new wealth also fed political conflict inside Chile. Disputes over how nitrate revenues should be spent, and over the balance of power between the president and Congress, contributed to the Chilean Civil War of 1891, in which forces backing Congress defeated President José Manuel Balmaceda. Nitrate towns in the desert, such as Humberstone, later became symbols of the harsh conditions of mining labour.

Peru suffered heavy destruction and a long political and economic crisis, while the loss of Tarapacá’s revenues deepened its debts. Bolivia became landlocked, a loss that has remained central to its national identity; it marks a Day of the Sea every 23 March, the anniversary of Eduardo Abaroa’s death at Topáter in 1879.

The dispute over sea access has repeatedly returned to diplomacy. In 2018 the International Court of Justice ruled that Chile was not legally obliged to negotiate sovereign access to the sea for Bolivia, though it encouraged continued dialogue. Bolivia’s later conflict with Paraguay in the Chaco War was driven in part, many historians argue, by the hope of gaining an outlet to the Atlantic along the Paraguay River.

Timeline

• 1874, 6 August: Chile-Bolivia boundary treaty fixes the border and freezes taxes.
• 1879, 14 February: Chile occupies Antofagasta.
• 1879, 5 April: Chile declares war on Peru and Bolivia.
• 1879, 21 May: Battle of Iquique; Esmeralda sunk, Arturo Prat killed.
• 1879, 8 October: Battle of Angamos; Huáscar captured, Miguel Grau killed.
• 1880, 26 May: Battle of Tacna; Bolivia withdraws from active fighting.
• 1880, 7 June: Chilean troops take Arica.
• 1881, 17 January: Chilean army enters Lima.
• 1883, 20 October: Treaty of Ancón between Chile and Peru.
• 1884, 4 April: Truce of Valparaíso with Bolivia.

Legacy

The War of the Pacific was one of the largest conflicts in nineteenth-century South America, comparable in its long-term impact to the Paraguayan War of 1864-1870. Its heroes, Prat, Grau, Bolognesi, Cáceres and Abaroa, are commemorated in statues, street names and national holidays in all three countries. Historians still debate how far British commercial interests encouraged the conflict; most see them as an important background factor rather than the direct cause.

Why it matters

The war fixed the modern borders of the central Andes, turned Chile into a wealthy nitrate economy and left Bolivia landlocked. It shows how a single valuable commodity in a disputed desert could redraw the political map of a continent, and its aftermath still shapes relations between Chile, Peru and Bolivia.