Stephens Island is at the northernmost tip of the Marlborough Sounds in the South Island of New Zealand. It lies two kilometres to the northeast of Cape Stephens, the northernmost point of D'Urville Island. The island is 1.5 square kilometres in size, and rises 283 metres (928 ft) high from the sea.

D'Urville Island, Māori name Rangitoto ki te Tonga, is the largest island in the Marlborough Sounds, on the northern coast of the South Island of New Zealand. It was named after the French explorer Jules Dumont d'Urville. With an area of approximately 150 square kilometres (58 sq mi), it is the eighth-largest island of New Zealand, and has around 52 permanent residents. The local authority is the Marlborough District Council.