Hogan Island is a granite

Granite

Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

 island, with an area of 232 hectare (0.895757007934681 sq mi) and a high point of 116 metres (381 ft), in south-eastern Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. It is the largest of Tasmania

Tasmania

Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

’s Hogan Group, lying in northern Bass Strait

Bass Strait

Bass Strait is a sea strait separating Tasmania from the south of the Australian mainland, specifically the state of Victoria.-Extent:The International Hydrographic Organization defines the limits of the Bass Strait as follows:...

 between the Furneaux Group and Wilsons Promontory

Wilsons Promontory

Wilsons Promontory is a peninsula that forms the southernmost part of the Australian mainland and is located at . South Point at is the southernmost tip of Wilsons Promontory and hence of mainland Australia...

 in Victoria. The island was formerly used for the grazing of cattle, an activity which has ceased after causing considerable damage to the vegetation and the natural springs

Spring (hydrosphere)

A spring—also known as a rising or resurgence—is a component of the hydrosphere. Specifically, it is any natural situation where water flows to the surface of the earth from underground...

 there.

Fauna

Recorded breeding seabird

Seabird

Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...

 and wader

Wader

Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...

 species include Little Penguin

Little Penguin

The Little Penguin is the smallest species of penguin. The penguin, which usually grows to an average of in height and in length , is found on the coastlines of southern Australia and New Zealand, with possible records from Chile.Apart from Little Penguins, they have several common names...

, Short-tailed Shearwater

Short-tailed Shearwater

The Short-tailed Shearwater or Slender-billed Shearwater , also called Yolla or Moonbird, and commonly known as the muttonbird in Australia, is the most abundant seabird species in Australian waters, and is one of the few Australian native birds in which the chicks are commercially harvested...

 also known as the Mutton Bird, Pacific Gull

Pacific Gull

The Pacific Gull is a very large gull, native to the coasts of Australia. It is moderately common between Carnarvon in the west, and Sydney in the east, although it has become scarce in some parts of the south-east, as a result of competition from the Kelp Gull, which has "self-introduced" since...

, Silver Gull

Silver Gull

The Silver Gull also known simply as "seagull" in Australia, is the most common gull seen in Australia. It has been found throughout the continent, but particularly coastal areas. The South African Hartlaub's Gull and the New Zealand Red-billed Gull The Silver Gull (Chroicocephalus...

 and Sooty Oystercatcher

Sooty Oystercatcher

The Sooty Oystercatcher, Haematopus fuliginosus, is a species of oystercatcher. It is a wading bird native to Australia and commonly found on its coastline. It prefers rocky coastlines, but will occasionally live in estuaries....

. Reptile

Reptile

Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

s present are the Eastern Blue-tongued Lizard

Eastern blue-tongued lizard

The Eastern Blue-tongued Lizard is a subspecies of large skink which is common throughout Eastern Australia, often found in bushland and suburban areas where conditions are suitable...

, Metallic Skink

Metallic Skink

The Metallic Cool-skink or Metallic Skink is a species of skink in the Scincidae family. It is endemic to Australia, found in southern Victoria, as well as in Tasmania where it is the most widespread and common lizard, occurring on many offshore islands in Bass Strait as well as the mainland. It...

, Three-lined Skink, Bougainville's Skink

Bougainville's Skink

Bougainville's Skink is a species of skink in the Scincidae family. It is found in south-eastern Australia, including north-eastern Tasmania and many Bass Strait islands. It has very reduced limbs and moves in a snake-like manner. It is seldom seen as much of its life is spent beneath...

 and White's Skink

White's Skink

White's Skink is a species of skink in the Scincidae family. It is found in south-eastern Australia, including Tasmania and many Bass Strait islands. It is slow-growing, to a maximum length of about 90 mm, and may take four years to reach maturity. It gives birth to live young. It is...

.
Goats were present for some time also.

State border

The state border between Tasmania and Victoria lies in the Hogan Group and passes over land on the North East Islet, thus giving a land border between the two states. The original intention was that these Bass Strait Islands would be part of Tasmania, but the surveyed position for Wilson's Promontory was slightly off, and the border placed too far south at 39°12' S. Once this was discovered the Islet was renamed to Boundary Islet

Boundary Islet

Boundary Islet is an islet about 60,000 square metres in size in the Hogan Group of islands and islets at latitude 39°12' S, south of the Wilsons Promontory, the southernmost part of both mainland Australia and mainland Victoria...

. The land border is 85 metres (279 ft) long.