Southland District is a New Zealand territorial authority district that covers most of the southern end of the South Island as well as Stewart Island.

Stewart Island is New Zealand's third-largest island, located 30 kilometres south of the South Island, across the Foveaux Strait. It is a roughly triangular island with a total land area of 1,746 km2 (674 sq mi). Its 164-kilometre (102 mi) coastline is deeply creased by Paterson Inlet (east), Port Pegasus (south), and Mason Bay (west). The island is generally hilly and densely forested. Flightless birds, including penguins, thrive because there are few introduced predators. Almost all the island is owned by the New Zealand government, and over 80 per cent of the island is set aside as the Rakiura National Park.