There are in fact four places in Australia where three state borders meet, but only three are named. The reason one corner is unnamed is because it legally does not exist (or more accurately, it has never been defined). This unnamed, undefined corner is where the borders of New South Wales, South Australia and Victoria are supposed to meet. An error in calculating the line of longitude when the Vic/SA border was first surveyed was suspected in 1868 and confirmed in 1883.
The boundary was disputed by the South Australian and Victorian Governments and the matter was taken to the High Court of Australia in 1911. The issue was finally settled in 1914, when it the Privy Council ruled in favour of Victoria. Because of that decision the western boundaries of Victoria and New South Wales, which were intended to be a straight line, do not meet.
The New South Wales border is set at 141° east, some 3.6 kilometres to the east of the SA/Vic border. Both borders end at the Murray River but there is a 3.6 kilometre gap between their end points, so technically there is no place where the two borders acutally meet.
Surveyor Generals Corner (WA/SA/NT)
Surveyor Generals Corner (or Surveyor-Generals Corner) is a remote point where the Australian state boundaries of South Australia, Western Australia and the Northern Territory meet.
All of these boundaries meet at a single point, which is the easternmost point of the 127 metre section of the Western Australian border with the Northern Territory border which runs east-west along the 26th parallel south latitude to meet the western boundary of the South Australian border.
From 7 March 2003, access to the area was restricted following a decision by the Irrunytju (Wingellina) Community in whose traditional land the Surveyor Generals Corner is situated. Access to the area is limited to guided tours and visitors require a special permit in addition to the standard Great Central Road transit permit. The nearest settlement is the Aboriginal community of Kalka in South Australia, situated on the Gunbarrel Highway just a few kilometres to the south.
There are three occurrences of New Year's Eve at Surveyor Generals Corner (also in Cameron Corner and Poeppel Corner), because it is located at the intersection of three time zones. One interesting piece of trivia is that fewer people have visited this site than have been to the South Pole.
Where actually is the corner? When looking at the offical corner marker, anyone who knows their geography knows there is something not right here. Take a quick glance at most maps of Australia and you could be forgiven for thinking that, as the Western Australian border is a straight line, the line depicting the Western Australian border on the marker should be a straight line from one side of the marker to the other, and not the Northern Territory border. Nevertheless, the marker accurately depicts the border at that point. Let me explain.
The border which runs along the eastern edge of Western Australia is not actually one continuous straight line. In 1922 an agreement was signed between the prime minister W. M. Hughes, the acting premier for South Australia, Sir John George Bice, and the premier of Western Australia, Sir James Mitchell to set the border along the 129th meridian east longitude and defined the boundary by lines drawn north and south through the centre of the Deakin Obelisk, erected in 1926 near Deakin, Western Australia, and the Kimberley Obelisk, erected in 1927, near Argyle Downs, in the Kimberley Region of Western Australia.
When survey work began on the South Australia - Northern Territory border in 1963, it was quickly realised that the earlier agreement precluded the possibility of these lines meeting exactly. Precise survey methods confirmed this. On 4th June 1968, two concrete pillars were completed to mark Surveyor-Generals Corner in the presence V.T. O'Brien, Acting Director of Lands, N.T., P.J. Wells, Acting Surveyor-General, N.T.;H.A. Bailey, Surveyor-General, S.A.;Harold Camm, Surveyor-General, W.A.; and B.M. Allwright, Surveyor, N.T. The most easterly monument common to all three jurisdictions was named Surveyor Generals Corner at the suggestion of the Director of National Mapping and it is this monument that is shown here. The site is not named after a single Surveyor-General, because there were a number of them present as follows.
Poeppel Corner (NT/SA/QLD)
Poeppel Corner (known as Poeppels Corner in Queensland) at latitude 26° S and longitude 138° E is a corner of state boundaries in Australia, where the state of Queensland meets South Australia and the Northern Territory. As with the other three named corners, it is on the list of many four-wheel-drive tourists of "must visit" outback destinations.
Augustus Poeppel, after whom the point is named, conducted a survey in the mid-1880s to find the exact location of the central Australian state borders. His team used camels to drag a coolibah post to mark the intersection. Originally the point was located in a salt lake, however it was found that the measuring chain used was a few centimetres too long. Another survey was conducted by Lawrence Wells, who relocated the post to its current position.
New Year's Eve occurs three times in Poeppel Corner (also in Cameron Corner and Surveyor Generals Corner), because it's in the corner of three time zones.
Haddon Corner (SA/QLD)
Surveying the lengthy Queensland-South Australia border was no fun for the men assigned this task in the colonial era. Taking over from a predecessor forced off the job by ill-health, German-born South Australian surveyor Augustus Poeppel and his assistant Lawrence Wells forged north in 1880 along the line from Cameron Corner to the northeast tip of South Australia.
Meeting up with Queensland surveyor Alexander Salmond, they verified the latitude by astronomical observations and marked the corner with a wooden post set above an iron bar. Haddon Corner later took its name from that of a nearby pastoral lease.
There are no facilities at this location, but it's often visited as part of the Three Corners Itinerary of the Outback Loop which links the Birdsville Track and Strzelecki Track.
Cameron Corner (SA/QLD)
One of the most well known 'corners' of the Australian outback is Cameron Corner, where the borders of the states of New South Wales, South Australia and Queensland meet. Here you can hit a golf ball out of NSW, it will fly over part of Qld before landing in SA. This is also where one can celebrate the New Year three times (also in Poeppel Corner and Surveyor Generals Corner), because it s on the corner of three time zones. The roads and tracks in this region are generally earth-formed and corrugated but despite plenty of bulldust, are usually suitable for conventional vehicles with care.
Located about 1,400 kilometres west-southwest of Brisbane, Queensland, this corner is named for the surveyor, John Brewer Cameron, from the New South Wales Lands Department, who spent two years during 1880-82 marking the border between New South Wales and Queensland. Mr. Cameron erected a post there in September 1880 to mark its intersection with the border of South Australia. He placed a wooden marker every mile (1.6 km) eastwards along the interstate boundary.
This general area, which includes Sturt Stony Desert in the Lake Eyre Basin, was first explored by Captain Charles Sturt, who in 1844 went in search of a supposed inland sea in the center of Australia.
Boundary Islet (VIC/TAS)
An islet about 60,000 square metres in size in the Hogan Group of islands and islets to the south of the Wilson's Promontory, Boundary Islet straddles the border of the Australian states of Victoria and Tasmania. The boundary between the two states - 39°12' S - is a parallel that actually passes through the islet, making it Tasmania's only land boundary, and at 85 metres long it is the shortest land border between any Australian states. Boundary Islet is also about 56 kilometres east of the southernmost point of mainland Victoria. The position of the island was surveyed in 1801 by Captain James Black, who erred in placing the islet further north than it is.