Tarija Department in the far south of the country is Bolivia's smallest Department, covering an area of 37,623 km² / 14,526 sq miles; its capital is the city of Tarija. It is Bolivia's main wine producing region and also has significant reserves of natural gas. It was one of the first regions in South America to declare itself independent from the Spanish, separating in 1807 from Upper Peru to become part of the jurisdiction of Salta in what is now northern Argentina (culturally and historically it has much in common with neighbouring Argentina). After the Wars of Independence and foundation of the modern South American countries the Tarija region voted to become part of Bolivia in a referendum in 1826. The eastern half of the Department forms the Gran Chaco Province, an autonomous region.