The Otago harbour was formed by the sunken remnants of a shield volcano centered near what is now known as Port Chalmers. The last eruption of this particular volcano was around 10 million years ago. Another landmark formed by this volcano was Mount Cargill.
Captain Cook guessed the existence of the Dunedin Harbour when he first arrived here in 1770. When the harbour was first entered is unknown but is said to be "before 1810".
In the early 1800s the Dunedin harbour was very famous for the hunting and killing of whales and seals. A whaling station was set up by the Weller brothers in 1831. But this was later shut down in 1840 and a liquor trade took its place until the Scottish settlers arrived in 1848.
In 1882 New Zealand's frozen meat was exported from Port Chalmers.
Due to the gold rush more ships started docking in the Otago harbour. The Otago harbour was not built for ships to dock too close to the city. The harbour was just not deep enough. So the decision was made to dredge a channel to dock closer. The channel was dredged and first opened to ships in 1881. The channel was named the Victoria channel by Keith Ramsay chairman of the Otago harbour board.
Quarantine island is the largest island situated in the Dunedin harbour. The island acted as a quarantine for sick passengers coming of the boats from 1863 until 1924. These people were sent there until they either became well or passed away. There is a small cemetery on the island.
The Victoria's channel nowadays is used to get oil to Dunedin and to get fertiliser to Ravensbourne's fertiliser plants.
The Dunedin harbour stretches 21 KM southeast until it meets the Dunedin Pensiula.