Mercury BayNew Zealand
36°58′S 176°05′E
Aldermen Islands
Ruamahua
The Aldermen Islands are a small group of rocky islets to the southeast of Mercury Bay in the North Island of New Zealand. They are located off the coast of the Coromandel Peninsula, 20 kilometres (12 mi) east of the mouth of the Tairua River.

Chart
Overview
The Aldermen Islands are a small group of rocky islets to the southeast of Mercury Bay in the North Island of New Zealand. They are located off the coast of the Coromandel Peninsula, 20 kilometres (12 mi) east of the mouth of the Tairua River.
The islands were named 'the Court of Aldermen' by Captain Cook and his crew on 3 November 1769 after previously naming Mayor Island. The Aldermen group consists of four main islands: Hongiora, Middle, Ruamahuanui, and Ruamahuaiti. The smaller islands include Big Hump, Little Hump, Nga Horo Island, Half Island and The Spire. Their combined area is 133.5 ha (330 acres). The islands are a forested nature reserve hosting rare species including the tuatara. Access is by permit only. The Aldermen Islands are the remains of eroded Pliocene or Early Pleistocene lava domes that form part of the Whitianga Group. Approximately 18,000 years ago during the Last Glacial Maximum when sea levels were over 100 metres lower than present day levels, the islands were hilly features surrounded by a vast coastal plain. Sea levels began to rise 7,000 years ago, after which the islands separated from the rest of New Zealand. When sea levels were lower, the Tairua River flowed south of the features, travelling eastwards towards the Pacific Ocean.
From Wikipedia, CC BY-SA 4.0
Census, cataloged
- Major islands2
- Minor islands0
- Islets0
- Rocks & skerries0
Major islands
Ruamahuanui Island
- Area
- 0.32 km²
- High point
- 168 m
Ruamahuaiti Island
- Area
- 0.25 km²
- High point
- 182 m
Also in the area
Inside the group's outline but not confirmed as members by any source.
- Middle Island55 m · 0.23 km²
- Hongiora76 m · 0.16 km²
- Nga Horo Island10 m · 0.04 km²
- The Spire61 m · 0.02 km²
- Unnamed island25 m · 0.02 km²
- Half Island12 m · 0.01 km²
- Big Hump45 m · 0.01 km²
- Unnamed island6 m · 0.8 ha
- Unnamed island11 m · 0.5 ha
- Unnamed island2 m · 0.3 ha
- Unnamed island0.3 ha
- Unnamed island1 m · 0.2 ha
Figures
Comparative heights
- Ruamahuaiti: 182 m
- Ruamahuanui: 168 m
- Hongiora: 76 m
- The Spire: 61 m
- Middle: 55 m
- Big Hump: 45 m
- Half: 12 m
- Nga Horo: 10 m
To the same scale
Islands by area
| Ruamahuanui Island | 0.32 km² |
| Ruamahuaiti Island | 0.25 km² |
| Middle Island | 0.23 km² |
| Hongiora | 0.16 km² |
| Nga Horo Island | 0.04 km² |
| The Spire | 0.02 km² |
| Unnamed island | 0.02 km² |
| Half Island | 0.01 km² |
| Big Hump | 0.01 km² |
| Unnamed island | 0.8 ha |
| Unnamed island | 0.5 ha |
| Unnamed island | 0.3 ha |
| Unnamed island | 0.3 ha |
| Unnamed island | 0.2 ha |
| Unnamed island | 0.2 ha |
| Unnamed island | 0.1 ha |
| Unnamed island | 0.1 ha |
| Unnamed island | 0.1 ha |
| Unnamed island | 0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Little Hump | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
| Unnamed island | <0.1 ha |
Photographs

View of rocky islets at the Aldermen Islands, New Zealand. Digital copy of a photo taken around 1991.

A bay on one of the Aldermen Islands, New Zealand. Possibly Middle Island. Digital copy of a photo taken around 1991.
Sailing in New Zealand, Alderman Islands at sunset
Sources
Facts
Photographs
- Aldermen Islands 2. Bryndlefly / CC BY-SA 3.0
- Aldermen Islands 1. Bryndlefly / CC BY-SA 3.0
- Sailing in New Zealand PC156351. Peter Southwood / CC BY-SA 3.0
- The Aldermen Islands 01. Krzysztof Golik / CC BY-SA 4.0
- Alderman Islands banner 1. Peter Southwood / CC BY-SA 3.0
- Alderman Islands banner 2. Peter Southwood / CC BY-SA 3.0