South America 1881: Partition of Patagonia

When the War of the Pacific broke out in 1879, the Argentinians declared neutrality but remained sympathetic to Bolivia and Peru in their struggle against Chile. Despite this, in 1881, Argentina agreed to a boundary treaty with Chile, dividing Patagonia between them and accepting Chilean control of the Strait of Magellan.

Main Events

19 Nov–22 Dec 1880 Pisco-Curayaco landings

In September 1880 Chilean Captain Patricio Lynch landed forces in Chimbote and other northern Peruvian ports. When this failed to convince the government of Peru to come to terms, Chile disembarked 8,800 troops at Pisco, south of Lima, on 19-20 November. More forces joined them in early December, with another 14,000 being landed at Chilca and Curayaco—on the road north to Lima—on 22 wikipedia

13–17 Jan 1881 Fall of Lima

24,000 Chilean troops under the command of General Manuel Baquedano advanced on Lima, defeating the forces of Peruvian General Miguel Iglesias at Chorrillos by midday 13 January. After a temporary ceasefire at Miraflores, the Chileans resumed their offensive on 15 January, prompting President Nicolas de Piérola to withdraw to Tarma in the Andes. The mayor offered to surrender Lima the following day, and on the 17th a select regiment of 3,000 Chilean soldiers marched into the Peruvian wikipedia

12 Mar–28 Sep 1881 Calderón’s government

Following the fall of Lima, the Provisional Government of the Republic of Peru was declared in the still-unoccupied coastal district of Magdalena under the presidency of lawyer Francisco García Calderón. Calderón immediately entered into negotiations with the Chilean invaders, but, when the US-mediated peace talks collapsed, the Chilean governor—General Patricio Lynch—ordered his troops to occupy Magdalena on 28 September. Despite this, Calderón continued to refuse Chilean demands, eventually leading to his arrest and transportation to Chile aboard the Cochrane on 6 wikipedia

23 Jul 1881 Boundary Treaty of 1881

Bernardo de Irigoyen, representing Argentina, and Francisco de Borja Echeverría, representing Chile, signed the Boundary Treaty of 1881 in Buenos Aires, Argentina. The treaty confirmed the Andes as the boundary between the two countries and partitioned the disputed region of Patagonia on this basis; in the south, straight lines were drawn to give Argentina the Atlantic coast and Chile the Pacific coast including the land around the Strait of Magellan (which was recognized as a neutral and freely navigable waterway).in wikipedia