Border Lengths - States and Territories

Last updated:7 June 2023

Coastline lengths

The total coastline length for a state or territory includes both its mainland coastline and the length of all islands in that jurisdiction.

The accuracy of the length of coastline depends on the scale of the maps used to make the determination (the table above uses Geoscience Australia's GEODATA Coast 100K 2004 database, in a GDA_1994_Australia_Albers projection). However, new technologies now being used will allow coastline length measurement to become more detailed and coastline lengths will be increased.

Australia is the sixth largest country in the world and is the only one of the top six completely surrounded by water. The mainland and Tasmania also are surrounded by many thousands of small fringing islands and numerous larger ones. Almost forty per cent of the total coastline length comprises island coastlines. As an island nation, coastlines play an important role in defining National, State and Territory boundaries.

Calculations on Australia's coastline lengths are taken from Geoscience Australia's GEODATA Coast 100K 2004 database. The coastline data is nationally uniform, is sourced primarily from the 1:100 000 scale National Topographic Map Series and is the most authoritative data currently available on the length of the entire Australian coastline and the State and Territory coastlines as described in the Maritime Boundary Definitions.

Land border and coastline lengths between Australia's states and territories.

State/Territory Land border length Mainland coastline length Island length Total coastline length
Western Australia 1 874 12 895 7 894 20 788
Queensland 3 337 6 967 6 385 13 352
Northern Territory 3 180 5 438 5 516 10 954
South Australia 3 187 3 815 1 244 5 059
Tasmania - 2 827 2 046 4 872
Victoria 2 550 1 870 645 2 515
New South Wales 4 625 1 973 128 2 101
Australian Capital Territory 306 - - -
Jervis Bay Territory 21 36 3 39
AUSTRALIA - 35 821 23 860 59 681

Lengths measured in kilometres. Source: GEODATA Coast 100K 2004

Border histories

The definition of where state and territory boundaries lie has been constantly reviewed, sometimes causing great contention. Although most of the boundaries were defined in letters of patent by meridians, determining the physical ground position that corresponds with those meridians has never been easy.

Floods, droughts, and frequent lack of supplies were just a few of the challenges dealt with by colonial surveyors. Facing the same harsh conditions as early explorers in Australia, surveyors also had a difficult job to do. Errors in the astronomically determined positions of observatories in Melbourne and Sydney didn't help matters either as surveyors of the time relied heavily on tying their observations back to known coordinate positions.

Given the possibility of discrepancies, border disputes have occurred between several states. Generally speaking, rulings have upheld the position of borders with established physical references or property lines. This is despite the advent of technologies which allow modern surveyors to accurately plot their location as originally described in the letters of patent for the formation of specific states. As a result, few state borders are actually where they were originally intended, or as simple as a straight line marked by a meridian of longitude.

A Federation in these Seas is a useful document describing the history of the acquisition of Australia's external territories.

Border facts

The Australian Capital Territory is the only land-locked state or territory in Australia, and Tasmania the only island state. The Northern Territory is the only jurisdiction which has a shorter mainland coastline than the combined coastline of all its islands.

Longest Land border

New South Wales has the longest land border of all the states and territories. It adjoins Queensland, South Australia, Victoria, the Australian Capital Territory and Jervis Bay Territory, making a total of 4 635 kilometres.

Shortest Land border

The Jervis Bay Territory land border with NSW is the shortest at 32 kilometres.

Corners of South Australia.

State/TerritoryLand border lengthMainland coastline lengthIsland lengthTotal coastline length
South Australia 3 185 3 816 1 251 5 067

Lengths measured in kilometres.

South Australia shares a border with all the mainland states as well as the Northern Territory. Where the border meets another state, or changes direction, the corner has been officially named, except where it meets the New South Wales - Victorian border. Each of the corners is marked with a concrete pillar.

'Corners' of the South Australian border.



Surveyor General's Corner

26° S 129° E


Poeppel Corner

26° S 138° E


Haddon Corner

26° S 141° E


Cameron Corner

29° S 141° E


MacCabe Corner

34° S 141° E

Western Australia - South Australia - Northern Territory border.

State/Territory Land border length Mainland coastline length Island length Total coastline length
Western Australia 1 862 12 889 7 892 20 781

Lengths measured in kilometres.

A glance at most maps of Australia will tell you something that isn't quite true. The border which runs along the eastern edge of Western Australia is not actually one continuous straight line.

The survey of the Western Australian border was first discussed in 1911, but it wasn't until 1922 that an agreement was signed between then Prime Minister W.M. Hughes, the Acting Premier for South Australia, Mr. Bice, and the Premier of Western Australia, Sir James Mitchell. The agreement set out the border as being a line determined by the 129th meridian east longitude. However, the agreement required that the boundary be defined by lines running north and south from independently fixed points at Deakin and Argyle. 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 and in June 1968 two monuments approximately 127 metres apart were erected at the junction of the boundaries. This ceremony was attended by the respective Surveyors General, H.Comm from Western Australia, H.A. Bailey from South Australia, and P.J. Wells from the Northern Territory. The monuments common to all three jurisdictions was named Surveyor General's Corner at the suggestion of the Director of National Mapping. One interesting piece of trivia is that fewer people have visited this site than have been to the South Pole.

Queensland - New South Wales border.

State/TerritoryLand border lengthMainland coastline lengthIsland lengthTotal coastline length
Queensland 3 339 6 973 6 374 13 347

Lengths measured in kilometres.

Letters of patent dated 6 June 1859 defined the boundary between Queensland and New South Wales as lying between Point Danger following watersheds and rivers to the line of parallel of 29° south. The survey was carried out between 1863 and 1866 from Point Danger to the Dumaresq River. Performed by Francis Roberts of Queensland and Isiah Rowland of New South Wales, the two were supposed to work together but when a falling out between them occurred, the pair each completed a separate survey. New South Wales records of the survey were destroyed in a fire and both State Governments settled on the Queensland survey.

From 1879 to 1881 the section between the Barwon River and the South Australian border was surveyed at 29° south latitude by George Watson of Queensland, and John B Cameron of New South Wales. The pair battled several floods and a drought to complete the job. The corner marked at the boundaries of Queensland, New South Wales and South Australia bears Cameron's name today.

In 2001, modern surveyors retraced the steps of Rowland and Roberts as part of a Centenary of Federation project, and found a 200 metre error. On the surface this may not seem like much to be concerned about, but the error occurs at the point on the New England Highway where the twin towns of Wallangarra (Queensland) and Jennings (New South Wales ) are located. Established in 1885, indications are that the originally intended boundary would put most of Jennings squarely inside Queensland. In an area where loyalty to state-based sporting teams, businesses, and beer is practically religious, declaring one town to actually be in another state is tantamount to heresy according to locals. Public sentiment is that Jennings has always been in New South Wales and always will be.

Victoria - New South Wales border.

State/TerritoryLand border lengthMainland coastline lengthIsland lengthTotal coastline length
New South Wales 4 635 2 007 130 2 137

Lengths measured in kilometres.

When Victoria was made a colony separate from New South Wales in 1851, there was much discussion about where the border should lie. With natural boundaries being in favour at the time, one proposal was to make the Murrumbidgee River the boundary. After much argument, it was eventually decided to define the border as a bearing from Cape Howe, which is the eastern-most point of Victoria, to the nearest source of the River Murray and from there along the river's course to the border with South Australia. The use of a river as a boundary has caused many arguments and debates between the states. Originally it was thought that doing so would cause less disputes and require less maintenance, but as trade and tariffs became more important in the early days, the Murray also grew in importance as a major trading route. The river has changed it's course in some places over time and because the jurisdiction of New South Wales extends to the southern high bank of the River Murray, this may change the status of some land parcels affected by the river's meandering path.

In 1859, New South Wales claimed the pastoral leases of Pental Island near Swan Hill on the grounds that the island lay to the north of the watercourse of the River Murray. In 1872, the case was decided in Victoria's favour when the Privy council maintained that the main watercourse, being the channel of greatest discharge of the Murray, was to the north of the island.

The line of bearing between the start of the River Murray and Cape Howe was explored and marked between 1870 and 1872 by Surveyors Alexander Black and Alexander Allan. In 1984 this line was resurveyed by the Department of Surveying, Royal Melbourne Institute of Technology, and the section of the border was renamed The Black-Allan line in honour of those first surveyors.

Victoria - South Australia border.

State/TerritoryLand border lengthMainland coastline lengthIsland lengthTotal coastline length
Victoria 2 541 1 868 644 2 512

Lengths measured in kilometres.

The border between South Australia and Victoria has an interesting history. It was to have been surveyed along the 141st meridian of longitude. However, through a series of miscalculations the line was originally positioned 3.6 kilometres further to the west. Lines of longitude were difficult to calculate in the 1800's because long distances travelled were measured off by chains which need to be gradually adjusted to compensate for the lines of longitude drawing closer together as one moves away from the equator.

In this case, the two methods used to record longitude gave differing results, so an average distance was chosen. To further complicate the issue, no adjustment was made to the chains to allow for the distance south of the Equator. As a consequence, the border runs north in a series of steps until it reaches the River Murray. The two surveyors, Wade and White, managed to survey 450 kilometres of the border between them. They were forced to stop a number of times due to lack of funding and equipment. In 1849, White ran out of water, and lost several bullocks and horses before reaching safety. The survey was finally completed in 1850.

The error in calculating the line of longitude 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 the Privy Council upheld the ruling in favour of Victoria. It is an interesting point to note that because of this decision, the western boundaries of Victoria and New South Wales do not meet. The New South Wales border is set at 141° east, leaving a section of boundary between Victoria and South Australia that is undefined along the River Murray, measuring 3.6 kilometres from east to west.

Australian Capital Territory - New South Wales border.

State/TerritoryLand border lengthMainland coastline lengthIsland lengthTotal coastline length
Australian Capital Territory 306 - - -

Lengths measured in kilometres.

After Federation in 1901 it was decided that a seat of government for the new nation should be selected. The new capital would not be selected from existing state capitals to prevent further rivalry, particularly between Melbourne and Sydney. Several possible locations were suggested, including Albury, Armidale, Bombala, Lake George, Orange and Tumut.

In 1903, the House of Representatives initially selected the Bombala region by ballot but a change of government in 1904 favoured Dalgety and when political fortunes reversed again in 1905 the question was thrown open once more. Three areas were considered and visited by parliamentarians in 1906; Dalgety, the Canberra region and Lake George. John Gale, then proprietor of the Queanbeyan Age, pressed the virtues of Canberra in glowing terms while the counter claims of Dalgety were promoted vigorously.

Neither the Federal Parliament nor the New South Wales State Government were easily convinced and on 9 October, 1908 a ballot win of six votes selected the Yass-Canberra region to be the location of the national capital. Yass-Canberra was defined as a triangle, with Yass at the top corner, Lake George to the east and the Murrumbidgee to the west.

The national capital was known originally as the Federal Capital Territory and was formally transferred from New South Wales on 1 January 1911. Land-locked, the Federal Capital Territory acquired a port when Jervis Bay was transferred from NSW in 1915. On 29 July 1938, the Federal Capital Territory was officially legislated as the Australian Capital Territory.