Kefalonia (Modern Greek: Κεφαλλονιά or Κεφαλονιά), is the largest of the Ionian Islands in western Greece with an area of 564 square kilometres. The island is named after the mythological figure Cephalus (Ciphalis), although some believe its name literally means 'an island with a head, referring to the island's shape, because the name 'Ciphalis' is derived from the Greek word for 'head'. The island is covered by dense vegetation and offers plentiful natural beauty including beaches, many of them inaccessible from land, and spectacular caves. Mirtos, the most famous of these beaches, is a major tourist attraction, and has been ranked fifth worldwide for its scenic view. Kefalonia's tallest mountain is Mount Ainos, (1,628 metres). To the north west are the Paliki mountains, where Lixouri is located. Other mountains include Gerania and Agia Dynati. Kefalonia has one airport, Kephallinia Airport, which is ten kilometres south of Argostoli.

Kefalonia is located in the heart of an earthquake zone. Dozens of minor tremors occur each year. In 1953, a massive earthquake almost destroyed the island, leaving only Fiscardo in the north untouched.