The Cenepa War or Fourth Ecuadorian-Peruvian War, also known as the Alto Cenepa War, was a brief and localized military conflict between Ecuador and Peru, fought over control of an area in Peruvian territory near the border between the two countries. The two nations had signed a border treaty following the Ecuadorian–Peruvian War of 1941, but Ecuador later disagreed with the treaty as it applied to the Cenepa and Paquisha areas, and in 1960 it declared the treaty null and void. Most of the fighting took place around the headwaters of the Cenepa River.