Pelorus Sound / Te Hoiere is the largest of the sounds which make up the Marlborough Sounds at the north of the South Island, New Zealand. The Marlborough Sounds is a system of drowned river valleys, which were formed after the last ice age around 10,000 years ago. Pelorus Sound has a main channel which winds south from Cook Strait for about 55 kilometres (34 mi), between steeply sloped wooded hills, until it reached its head close to Havelock town. Pelorus has several major arms, notably Tennyson Inlet, Tawhitinui Reach, Kenepuru Sound and the Crail/Clova/Beatrix Bay complex. Its shoreline runs for 380 kilometres (240 mi).
Industry in Pelorus Sounds is based around marine farming, pine forestry and some tourism. Private holiday homes are becoming more common. Most of the settled places are hard to reach overland, and are serviced by the Pelorus Express, a mail boat which does three different weekly runs from Havelock.
Maud Island, originally called Te Hoiere in the Māori language, is a 310-hectare (770-acre) island in the Pelorus Sounds. It is an important nature reserve to which only scientists and conservationists have access.
The local iwi (tribe) of the indigenous people of New Zealand is the Ngāti Kuia. According to Ngāti Kuia oral tradition, their founding father, a descendant of Kupe, came to the South Island in his waka Te Hoiere.
In 1642, Abel Tasman sailed past D'Urville Island. French and Russian explorers followed and in the 1770s Captain James Cook arrived.