Preveza is a city in the region of Epirus, northwestern Greece, located on the northern peninsula at the mouth of the Ambracian Gulf. It is the capital of the regional unit of Preveza, which is part of the region of Epirus. The Aktio-Preveza Immersed Tunnel – the first and so far only undersea tunnel in Greece – was completed in 2002 and connects Preveza in the north to Aktio in western Acarnania in Aetolia-Acarnania south of the mouth of the Ambracian Gulf. The ruins of the ancient city of Nicopolis lie 7 kilometres north of the city.