Ninety Mile Beach is a beach located on the western coast of the far north of the North Island of New Zealand. It stretches from just west of Kaitaia towards Cape Reinga along the Aupouri Peninsula. It begins close to the headland of Reef Point, to the west of Ahipara Bay, sweeping briefly northeast before turning northwest for the majority of its length. It ends at Scott Point, five km south of Cape Maria van Diemen.

The name Ninety Mile Beach is a misnomer because it is actually 88 km (55 miles) long. The reason for its name is unknown. Several theories have been put forward, the most common stemming from the days when missionaries travelled on horse back. On average a horse could travel 30 miles in a day before needing to be rested. The beach took three days to travel therefore earning it the title Ninety Mile Beach, but the missionaries did not take into account the slower pace of the horses walking in the sand, thus thinking they had travelled 90 miles when in fact they had only travelled 60.