structural:summarization
Chilean and Argentine colonization (1843–1902)

In the early 19th century, the araucanization of the natives of northern Patagonia intensified, and many Mapuches migrated to Patagonia to live as nomads that raised cattle or pillaged the Argentine countryside. The cattle stolen in the incursions (malones) were later taken to Chile through the mountain passes and traded for goods, especially alcoholic beverages. The main trail for this trade was called Camino de los chilenos and runs a length around 1000 km from the Buenos Aires Province to the mountain passes of Neuquén Province. The lonco Calfucurá crossed the Andes from Chile to the pampas around 1830, after a call from the governor of Buenos Aires, Juan Manuel de Rosas, to fight the Boroano people. In 1859, he attacked Bahía Blanca in Argentina with 3,000 warriors. As in the case of Calfucura, many other bands of Mapuches got involved in the internal conflicts of Argentina until Conquest of the Desert. To counter the cattle raids, a trench called the Zanja de Alsina was built by Argentina in the pampas in the 1870s.

In the mid-19th century, the newly independent nations of Argentina and Chile began an aggressive phase of expansion into the south, increasing confrontation with the Indigenous peoples of the region. In 1860, French adventurer Orelie-Antoine de Tounens proclaimed himself king of the Kingdom of Araucanía and Patagonia of the Mapuche.

Following the last instructions of Bernardo O'Higgins, the Chilean president Manuel Bulnes sent an expedition to the Strait of Magellan and founded Fuerte Bulnes in 1843. Five years later, the Chilean government moved the main settlement to the current location of Punta Arenas, the oldest permanent settlement in Southern Patagonia. The creation of Punta Arenas was instrumental in making Chile's claim of the Strait of Magellan permanent. In the 1860s, sheep from the Falkland Islands were introduced to the lands around the Straits of Magellan, and throughout the 19th century, sheepfarming grew to be the most important economic sector in southern Patagonia.

George Chaworth Musters in 1869 wandered in company with a band of Tehuelches through the whole length of the country from the strait to the Manzaneros in the northwest, and collected a great deal of information about the people and their mode of life.