[13] During the early years of the post-war era, the Chilean and Peruvian governments exercised extensive campaigns to solidify their control over the region.

On one hand, Peru established a campaign of foreign support, which attracted the attention of the United States as a mediator in the conflict.

The creation of the Department caused controversy in Peru, due to both countries disagreeing on their border in the Sama River.

While the Chilean government argued the town was to the east of the river, the border agreed upon by both countries, Peru disputed this claim on the grounds that the territory was not affected by the Treaty of Ancón and established a policy of non-recognition.

Then dictator of Peru Francisco Morales-Bermúdez was opposed to these changes but proposed to make Arica a territory governed by the three states.

[35] Since Pinochet was likely aware that the Charaña proposals would fail in the end due to Peruvian opposition, legal and political analysts have suggested that he raised them just as a gesture towards Bolivia.

[37][38] Around the same time, from 1968 to 1980, President Juan Velasco Alvarado once again referred to Arica and Tarapacá with the term captive provinces.

The maritime dispute between Chile and Peru concerned the sovereignty of an area in the Pacific Ocean approximately 37,900 square kilometres (14,600 sq mi) in size.

A dispute regarding a milestone known as Milestone 1 or Concordia Point (Spanish: Hito 1 / Punto Concordia) and the area it establishes, known as the land triangle (Spanish: triángulo terrestre), was revived as a result of the ICJ ruling, due to the disagreement on where the new maritime border was to begin.

Both countries also claim to patrol the area, the former with the Quebrada de Escritos observation point and the latter with the Francisco Bolognesi outpost.

Peru established the La Yarada-Los Palos District in 2015, with its borders once again alluding to the disputed area.