This article is about the city in Peru. For other meanings, see Tacna (disambiguation).

Tacna is a city in southern Peru, located only 35 km north from the border with Chile. Its original name is La Heroica Ciudad de San Pedro de Tacna, and it is the capital of the Tacna province and the Tacna region. Tacna is located in the Atacama Desert near the Pacific Ocean.

Many monuments are located in Tacna, including the arch of the Alto de la Alianza, which shows the significance of this town. In 1828, President José de La Mar declared Tacna as the "Heroic City". During the War of the Pacific, the cities of Tacna and Arica were invaded by Chilean forces. A peace agreement, the Treaty of Ancón was signed in 1883. Under the terms of the treaty, Chile was to occupy the provinces of Tacna and Arica for 10 years, after which a plebiscite was to be held to determine their nationality. Tacna lived a period of captivity for 50 years; the invaders started a campaign of "Chilenization", whose purpose was to convince the local population of accepting Chile as the new ruling power, and make them lose their Peruvian identity. Nevertheless, the patriotism of the tacneños hindered the Chilean attempts of gaining their sympathy, which was needed for getting their vote at the plebiscite. The plebiscite was never held, though. Finally, in 1929, an accord was reached by which Chile kept Arica; Peru reacquired Tacna and received $6 million indemnity and other concessions.

Other monuments include a neo-Renaissance Cathedral, the Alameda Bolognesi Walkway and the caves of Toquepala , where archaeologists have found some of the oldest human remains in Peru. In September, the festival of the Señor de Locumba is celebrated, which draws thousands of faithful people from all over the world.

Since it is part of a duty free zone, Tacna is the main area for business in southern Peru. The city has one of the largest artifact markets in the world, with things from Japan to China, and also traditional Peruvian handicrafts.