Perú v. Chile (also called the Chilean–Peruvian maritime dispute or the Case concerning the Maritime Dispute between the Republic of Peru and the Republic of Chile) was a case in public international law concerning a long-standing disagreement between Peru and Chile over the location of their maritime boundary in the Pacific Ocean. Peru maintained that no treaty had ever fixed a maritime boundary between the two countries and asked for an equitable division of the overlapping 200-nautical-mile zones claimed by each state; Chile maintained that the boundary had already been settled, running along the parallel of latitude that meets the coast at the end of the two countries' land border, by agreements the two countries signed together with Ecuador in 1952 and 1954.
On January 16, 2008, Peru submitted the dispute to the International Court of Justice (ICJ) in The Hague. After six years of written and oral proceedings, the Court delivered its judgment on January 27, 2014. It found that a maritime boundary along the parallel of latitude passing through Boundary Marker No. 1 had indeed been tacitly agreed by the parties, but only for a distance of 80 nautical miles from the coast; beyond that point, the Court drew a new boundary running southwest along a line equidistant from the coasts of the two countries out to 200 nautical miles. The ruling gave Peru sovereign rights over roughly 50,000 square kilometers (19,300 square miles) of the Pacific Ocean that Chile had previously treated as part of its exclusive economic zone or as high seas, while confirming Chile's rights over the waters closest to its own coast, including most of the area's richest fishing grounds. Both governments pledged to abide by the decision, and representatives of the two countries signed an act fixing the precise geographic coordinates of the new boundary on March 25, 2014.
Background
Treaties of Ancón and Lima (1883–1930) The War of the Pacific left the land border between Chile and Peru unsettled for nearly half a century. The 1883 Treaty of Ancón and the definitive 1929 Treaty of Lima fixed the land boundary, providing that it would run from a point on the coast to be called "Concordia," located ten kilometers north of the bridge over the Lluta River, and would be demarcated on the ground by a mixed boundary commission. A joint Chilean–Peruvian commission carried out the physical demarcation in 1930. Because the exact point where an arc drawn ten kilometers from the Lluta bridge met the shoreline lay in terrain that could be washed away by the sea, the commission's final act of July 12, 1930, placed the physical marker — "Hito No. 1" — about 180 meters inland from the water's edge, at coordinates the commission described as located at the "seashore" (orilla del mar). This distinction between the notional coastal terminus of the boundary (which Peru later called the "Concordia Point") and the physical marker inland from it (which Chile treated as the terminus) became one of the central technical disputes between the two countries.
1947 unilateral declarations Following a September 1945 proclamation by U.S. President Harry S. Truman asserting American jurisdiction over resources of the continental shelf, several Latin American governments issued similar unilateral claims. On June 23, 1947, Chilean President Gabriel González Videla declared national sovereignty over the sea adjacent to Chile's coasts out to 200 nautical miles, without prejudice to the legitimate rights of other states on a reciprocal basis. On August 1, 1947, Peruvian President José Luis Bustamante y Rivero issued a similar declaration by Supreme Decree No. 781, asserting sovereignty and jurisdiction over the sea adjacent to Peru's coasts out to 200 nautical miles, while explicitly reserving the right to modify the demarcation of these zones in light of future discoveries and national interests.
The 1952 Declaration and the 1954 agreements On August 18, 1952, Chile, Ecuador, and Peru signed the Declaration of Santiago (Declaración sobre Zona Marítima) at a conference on the exploitation and conservation of the marine resources of the South Pacific. The declaration proclaimed each state's exclusive sovereignty and jurisdiction over the sea within 200 nautical miles of its coast and provided that, in the case of island territories, the 200-mile zone of an island less than 200 miles from another signatory's general maritime zone would be limited by the parallel of latitude passing through the point where the land boundary between the two states meets the sea. Peru later argued that this island clause, inserted at Ecuador's request because of its offshore islands, was the declaration's only reference to a parallel boundary and had no bearing on the continental coast shared by Peru and Chile, where no islands lie. Chile, for its part, argued that the clause simply reaffirmed a general rule that adjoining states' zones were already divided by the parallel.
To curb disputes with small-scale fishermen who often strayed across the frontier, the three countries signed the Special Maritime Frontier Zone Agreement in Lima on December 4, 1954. It established a "special zone," beginning 12 nautical miles from the coast and extending 10 nautical miles on either side of "the parallel that constitutes the maritime boundary between the two countries," within which the accidental presence of small vessels of one country in the waters of the other would not be treated as a violation. Peru later characterized the accord as a practical fisheries measure rather than a boundary treaty, while Chile argued that the text's own wording presupposed the prior existence of a maritime boundary running along the parallel.
The 1968–1969 lighthouse arrangements Following complaints about the seizure of fishing vessels near the frontier, Peru and Chile in 1968 agreed to build lighted markers to help fishermen visually locate "the parallel of the maritime boundary originating at Boundary Marker No. 1." Technical delegations from both countries signed acts in April 1968 and August 1969 recording the site selection and completion of the two lighthouses, which were built and lit in 1972. Peru later argued that the commissions in question had been tasked only with erecting navigational aids for artisanal fishermen, not with demarcating or confirming any maritime frontier, and that the acts' references to a "maritime boundary" reflected imprecise drafting. Chile treated the acts as evidence that both countries recognized an existing maritime boundary along the parallel. Peru's lighthouse was damaged in an earthquake and dismantled in December 2001; the episode prompted a formal diplomatic protest from Chile after machinery entered Chilean-administered territory to remove debris.
The 1982 UN Convention on the Law of the Sea The Third United Nations Conference on the Law of the Sea produced the 1982 United Nations Convention on the Law of the Sea (UNCLOS), which set the territorial sea at 12 nautical miles and the exclusive economic zone at 200 nautical miles measured from baselines, and which specified that, absent historic rights or special circumstances, adjoining or opposite states should delimit their territorial seas along a median line equidistant from their respective baselines. Chile ratified UNCLOS in 1997, entering reservations under Article 298 that excluded it from the convention's compulsory dispute-settlement procedures for maritime boundary disputes — leaving the ICJ as the only forum with jurisdiction over such a dispute involving Chile. Peru signed UNCLOS in 2001 but, citing its constitutional claim to a 200-nautical-mile maritime domain, has not ratified it.
The 1986 Bákula memorandum Peru's Foreign Minister Allan Wagner first raised the question of a maritime boundary treaty with his Chilean counterpart, Jaime del Valle, in 1985. The following year, Peru's ambassador in Santiago, Juan Miguel Bákula Patiño, delivered a diplomatic note to del Valle, dated May 23, 1986, proposing formal negotiations to conclude "a treaty on maritime boundaries," on the premise that the delimitation of the two countries' maritime spaces remained formally undefined. Del Valle reportedly told Bákula in response that "the maritime boundary with Peru is a problem we have to study, and one we cannot put off indefinitely." Chile later argued before the Court that the exchange did not reflect an acknowledgment that no boundary existed, but rather Peru's own request to revise or clarify an already-settled line.
2004–2007 diplomatic exchanges On July 19, 2004, Peru's foreign minister, Manuel Rodríguez Cuadros, sent Chile's foreign minister, Soledad Alvear, a formal note proposing the opening of bilateral negotiations to fix the maritime boundary "through a specific treaty on the matter"; Chile's reply in September maintained that the 1952 and 1954 accords already constituted a boundary settlement. In November 2004, the two countries' foreign ministers issued a joint communiqué in Rio de Janeiro describing the disagreement over delimitation as "a matter of a legal nature" that was "strictly a bilateral issue" that should not interfere with the broader relationship between the two countries.
In 2005, Peru's Congress took up a bill to fix the baselines of the country's 200-nautical-mile maritime domain under Article 54 of the 1993 Constitution of Peru. The proposed baselines, running from the "Concordia Point," used the bisector method recommended under UNCLOS to divide the overlapping 200-mile zones with Chile in the south. The Peruvian Congress approved the bill unanimously (98–0) on November 3, 2005, and it was promulgated the same day as Law No. 28,621, the Law on the Baselines of Peru's Maritime Domain.
The bill's introduction, which had not previously been foreshadowed as a matter of urgency, provoked a sharp reaction in Chile, whose government, led by President Ricardo Lagos, rejected any Peruvian claim to waters south of the parallel through Boundary Marker No. 1; the National Congress of Chile approved a resolution backing the government's position. Peru's government called Chile's reaction disproportionate, and Bolivia and Ecuador — initially reluctant to become involved — eventually weighed in as well; on December 2, 2005, Chile and Ecuador signed an agreement reaffirming the validity of the 1952 and 1954 accords, which Peru's government criticized. In August 2007, following passage of the baselines law, Peru published new official charts depicting its 200-nautical-mile maritime domain, including the disputed trapezoid-shaped area and an adjoining "outer triangle" it labeled as an "area in controversy."
Chile lodged a formal objection to Peru's baselines law with the United Nations' Division for Ocean Affairs and the Law of the Sea in May 2007, and Peru responded with its own note in August 2007 reasserting that the demarcation of 1930 fixed the land boundary's coastal terminus at the "Concordia Point," not at Hito No. 1. Separately, a provision of a 2006 Chilean law creating the new Arica y Parinacota Region, which described "the parallel of Boundary Marker No. 1 in the Chilean Sea" as the region's northern limit, drew formal protests from Peru's foreign ministry; Chile's Constitutional Court struck the provision in January 2007 on a procedural ground unrelated to the merits of the boundary question.
2011 Peru–Ecuador exchange of notes