Actium, also known as Aktion or Aktio, is a peninsula on the mouth of the Ambracian Gulf in Acarnania, Greece, and the site of an ancient town of the same name. It is most known for the Battle of Actium, in which Octavian gained his celebrated victory over Antony and Cleopatra, on September 2, 31 BC. The peninsula has been connected to Preveza in Epirus since 2002 via the Aktio–Preveza Undersea Tunnel.