High Quality Content by WIKIPEDIA articles! The Otago Peninsula is a long, hilly indented finger of land that forms the easternmost part of Dunedin, New Zealand. Volcanic in origin, it forms one wall of the eroded valley that now forms Otago Harbour. The peninsula lies south-east of Otago Harbour and runs parallel to the mainland for 20 km, with a maximum width of 9 km. It is joined to the mainland at the south-west end by a narrow isthmus about 1.5 km wide.