1856 Argentina–Chile treaty
Treaty of Peace, Friendship, Commerce and Navigation between Chile and Argentina (1856)
- What it was: The first boundary treaty between Chile and Argentina, signed in 1856 to set terms for their relationship and borders.
- Key ideas:
- Boundaries would be based on uti possidetis, meaning the lines would follow what each country controlled at the start of their independence wars around 1810.
- If disputes arose, they should be settled through direct diplomatic talks and arbitration.
- Some issues, notably East Patagonia, Tierra del Fuego, and the Strait of Magellan, were postponed to be decided later.
- Article 40 set a 12-year limit on the treaty’s provisions about commerce and navigation.
- Later reference: The 1881 Boundary Treaty between Chile and Argentina mentions this 1856 treaty as fulfilling its Section 39.
- Background and context:
- Before signing, Chile had taken steps to assert control over the Strait of Magellan. In 1843, the Chilean government sent the schooner Ancud to seize the strait, led by Frigate Captain John Williams Wilson, with Fort Bulnes founded at Puerto del Hambre.
- Between 1852 and 1855, both countries conducted a detailed debate using many historical documents to support their claims.
- Chilean historian Miguel Luis Amunátegui argued in 1853 that the uti possidetis boundary should follow a 1775 map (excluding the Cuyo region, which Spain had transferred to Buenos Aires in 1776) and favored sovereignty up to the Río Negro.
- Argentina replied with a draft by Dalmacio Vélez Sarsfield in 1855; Amunátegui countered this view.
- Signing: The treaty was signed in 1856 amid these scholarly and political exchanges.
This page was last edited on 2 February 2026, at 14:03 (CET).