The Bay of Islands is in the Northland region in the far north of the North Island of New Zealand.
Located 60 km north-west of Whangarei, the bay is a natural harbour with an irregular 16 km wide inlet. Several sections of the bay extend into the land, notably Waikare Inlet in the south and Kerikeri and Te Puna (Mangonui) inlets in the north-west.
The small town of Russell is located at the end of a short peninsula that extends into the bay from the south-east.