Nicolás Avellaneda runs into trouble when he has to deal with the economic depression left by the Panic of 1873.

Most of these economic issues will be solved when new land is opened for work after the expansion of national territory through the Conquest of the Desert, led by his war minister Julio Argentino Roca.

This military campaign is to take most of the territories under control of natives, and reduce their population.

In 1875 Adolfo Alsina, Minister of War under Avellaneda, presents he government with a plan which he will later describe as ”aiming to populate the desert, and not to destroy the Indians”.

The first step is to connect Buenos Aires and the Fortines (fortresses) with telegraph lines.

Then a peace treaty is signed with chieftain Juan José Catriel, only to be broken shortly after when ...

...Catriel, together with chieftain Namuncurá and thirty-five hundred warriors, attacks Tres Arroyos, ...

...Tandil, ...

...Azul, and other towns and farms in an attack that is even bloodier than that of 1872.

Four hundred settlers are killed and three hundred captured, and three hundred thousand head of cattle are carried off.

Alsina answers by attacking the natives, forcing them to fall back, and leaving Fortines on his way south to protect the conquered territories.

He also constructs the three hundred and seventy-four kilometer-long trench named Zanja de Alsina ("Alsina's trench"), built in the center and south of the Buenos Aires Province, that in theory will serve as a limit to the unconquered territories.

With its three meter width and two meter depth, it serves as an obstacle for the transport of cattle by the natives.

South America Major (1876–1887 CE): Economic Growth, Abolitionist Advances, and Increased Foreign Influence

Between 1876 and 1887 CE, South America Major—encompassing Peru, Bolivia, Paraguay, Uruguay, Brazil, northern Argentina, northern and central Chile, Colombia (excluding Darién) and Ecuador (excluding the Ecuadoran capelands), Venezuela, Suriname, Guyana, and French Guiana—continued experiencing economic growth, infrastructure modernization, intensified abolitionist movements, significant foreign economic influence, and evolving political landscapes. This era set the stage for profound social and economic transformations across the region.

Political Developments

Gradual Political Stabilization

Many South American republics experienced relative political stabilization:

• Argentina consolidated national unity under President Julio Argentino Roca (1880–1886), strengthening federal authority and reducing regional fragmentation.

• Brazil remained politically stable under Emperor Pedro II, though tensions intensified due to slavery debates and economic modernization.

• Colombia continued its internal factional struggles, maintaining a precarious balance between Liberal and Conservative forces, with tensions building particularly in Panama due to neglect and dissatisfaction.

Recovery and Authoritarianism in Paraguay

Paraguay struggled slowly toward recovery after the devastating War of the Triple Alliance, undergoing political instability and authoritarian rule as factions vied to rebuild national institutions and stabilize the devastated economy.

Foreign Influence and Dependency

European (especially British) and North American economic influence significantly increased, with substantial investments in railways, ports, mining, and agriculture, deepening economic dependency across the continent.

Economic Developments

Export-Led Economic Growth

Export-driven economic expansion accelerated:

• Argentina and Uruguay significantly expanded beef, wool, and grain exports, fueling economic prosperity.

• Brazil experienced substantial coffee-export growth, becoming the world’s largest coffee producer and exporter.

• Chile and Peru relied on nitrates, guano, and minerals, despite territorial tensions that later led to regional conflict.

Foreign Investment and Infrastructure

Foreign capital notably financed railroads, telegraph lines, ports, and urban improvements, especially from Britain and increasingly from the United States, integrating regional economies more deeply into global markets.

Intensified Economic Dependency

Increasing foreign control over critical economic sectors heightened dependency on external markets and investment, shaping national policies and economic strategies significantly.

Cultural and Technological Developments

Growth of National Cultural Identity

Nations further cultivated national identities through literature, education, arts, and patriotic narratives. Cultural institutions, museums, and universities emerged as centers of national pride and intellectual engagement.

Urban Modernization and Development

Cities like Buenos Aires, Rio de Janeiro, Santiago, Lima, Montevideo, and Bogotá underwent extensive modernization. Urban planning, architecture, sanitation projects, and public transportation developed significantly, marking the era’s drive toward progress and modernity.

Social and Religious Developments

Accelerating Abolitionist Movements

Brazil experienced increased pressure from abolitionist groups, both domestically and internationally. Steps toward abolition advanced significantly:

• The Rio Branco Law (1871) had earlier freed children born to enslaved parents.

• The abolition movement intensified, foreshadowing slavery’s complete abolition in 1888.

Social Inequalities and Labor Movements

Social inequalities remained entrenched, though emerging labor movements in cities and plantations began challenging elite dominance. Early labor unrest and social activism appeared in urban centers, marking nascent political shifts.

The Catholic Church’s Evolving Role

The Catholic Church maintained cultural and educational influence, increasingly navigating tensions with secular liberalism. Church-supported charitable and educational institutions continued shaping social life, particularly amid rapid modernization.

Indigenous Resistance and Frontier Dynamics

Indigenous communities persistently resisted encroachment. Notably, frontier conflicts intensified:

• Argentina launched the controversial Conquest of the Desert (1879–1884), forcefully subjugating and displacing indigenous populations from Patagonia and northern territories, reshaping national territorial control at enormous human cost.

• Chile similarly intensified campaigns against the Mapuche (Pacification of Araucanía, ongoing through late nineteenth century), pushing indigenous peoples further into marginalization.

Long-Term Consequences and Historical Significance

The era from 1876 to 1887 CE significantly shaped South America Major's modern historical trajectory. Economic prosperity driven by exports and foreign investment established deeper dependency patterns influencing regional development. Advancements toward abolition foreshadowed major social transformations, particularly in Brazil. Indigenous displacement and frontier expansions revealed severe inequalities underlying modernization efforts. The era’s political stability, infrastructural expansion, and national identity formation created critical foundations for future political, social, and economic developments, even as they highlighted persistent tensions and unresolved conflicts.

President Julio Argentino Roca, who assumes the Argentine presidency in 1880, will rule almost without interruption for twenty-four years, despite student union- and military-led coup attempts in 1890, 1892, and 1893.

Argentina will finally vanquish the tribes of the Pampas during Roca’s long rule.

The so-called Conquest of the Desert occurs between 1878 and 1884: the appropriation of the indigenous lands triples the Argentine territory.

The Argentine government considers indigenous people as inferior beings, without the same rights as Criollos and Europeans.

The first conquest consists of a series of military incursions into the Pampa and Patagonian territories dominated by the indigenous peoples, distributing the conquered lands among the members of the Sociedad Rural Argentina, financiers of the expeditions.

Argentine authorities, concerned about the strong connections that araucanized tribes have with Chile, which allegedly gives Chile certain influence over the pampas, fear an eventual war with Chile over Patagonia in which the natives would side with the Chileans and that it would therefore be fought in the vicinities of Buenos Aires.

The decision to plan and execute what will be called the Conquest of the Desert, a controversial campaign by the Argentine government, had probably been triggered by the 1872 attack of Cufulcurá and his six thousand followers on the cities of General Alvear, Veinticinco de Mayo and Nueve de Julio, where three hundred criollos had been killed, and two hundred thousand heads of cattle taken.

Nicolas Avellanda, Argentina’s president from 1874, had run into trouble when he had to deal with the economic depression left by the Panic of 1873.

He names General Julio Roca as minister of war and tasks him to prepare a campaign that will bring and end to the "frontier problem" after the failure of the plan of Adolfo Alsina (his predecessor).

The natives frequently assault frontier settlements and steal horses and cattle, and the captured women and children are enslaved or offered as brides to the warriors.

Roca's approach to dealing with the native communities of the Pampas, however, is completely different from Alsina's, who had ordered the construction of a ditch and a defensive line of small fortresses across the Province of Buenos Aires.

Roca sees no way to end native attacks (malones) but by putting under effective government control all land up to the Río Negro in a campaign (known as the Conquest of the Desert) that will "extinguish, subdue or expel" the natives who inhabit the region.

This land conquest will also strengthen Argentina's strategic position against Chile.

Julio Argentino Roca devises a "tentacle" move, with waves of six thousand man-cavalry units stemming coordinately from Mendoza, Córdoba, Santa Fé and Buenos Aires on July 1878.

At the end of 1878 he starts the first sweep to "clean" the area between the Alsina trench and the Negro river by continuous and systematic attacks to the Indian settlements.

Elements of the Puán Division under Colonel Teodoro García clash with a war party at the Lihué Calel heights on December 6.

In a brief but hard fought battle, fifty natives are killed, two hundred and seventy are captured, and thirty-three settlers are freed.

Numerous armed encounters follow.

Roca begins the second sweep in 1879, with six thousand soldiers armed with new breech-loading Remington rifles, who reach Choele Choel in two months, after killing thirteen hundred and thirteen natives and capturing over fifteen thousand.

From other points, southbound companies make their way down to the Rio Negro River and the Rio Neuquén, a northern tributary of the Negro.

Together, both rivers mark the natural frontier from the Andes to the Atlantic Ocean.

This attack leads to a large migration of Mapuches into the zone around Curarrehue and Pucón, Chile.

Many settlements are built on the basin of these two rivers, as well as a number on the Colorado River.

Roca’s final defeat of the natives of the Pampas in 1879 opens the region to settlement by land-hungry Argentinians.