Casnell Island

Casnell Island is an uninhabited island located in the Mahurangi Harbour, Auckland Region, New Zealand.

Geography
The island is located in the Mahurangi Harbour at the mouth of Te Kapa River. It is accessible from Scotts Landing at low tide via a causeway. It is the largest island found in the Mahurangi Harbour.

The island is formed from Waitemata Group sandstone and mudstone.

Biodiversity
Much of the island is dominated by kanuka forest, with areas of pōhutukawa, kōwhai and grassland.

History
The island was a pā site in the 16th century, serving as a defensive fort at the entrance of the Mahurangi Harbour.