The borders of the State of Victoria include a few anomalies. Mostly they are amusing rather than troublesome.
Many of us think, for instance that Tasmania is on the colder side of Bass Strait, a fair way away, even by aeroplane, but it is much closer than we think. I should say, parts of it, because most of it is where we think it is. In fact, though, we Victorians have a land border with Tasmania. That border is really between Gippsland and Tasmania, too.
Before Victoria officially existed, and remember that Van Diemen's Land, later to be Tasmania, had settlements very early in the piece, it was decided that the colony of New South Wales would include all of the southern corner of the mainland, plus a small strip of coastal water. Van Diemen's Land would have all the islands in Bass Strait.
Then Victoria was 'colonised' and there was a need to set a boundary between it and the island state. That border was set at 39 degrees and 12 minutes south. Intended to just clear the Promontory. everyone was happy with that – until it was discovered that the original position of Wilson Promontory was not quite accurately fixed and that it reached to only 38 degrees and 93 minutes of south latitude.
The border had been set too far to the south. It wasn't really a problem except that the agreed line just clipped the northeast corner of the Hogan Group of islands, and that North West Island was actually astride the new border.
It was renamed Boundary Islet and it holds the only land border between Victoria and Tasmania. It doesn't matter too much because Boundary Islet is not much more than a large rock, with an exposed area of only 85 metres by 160. 
The shared land border between the two states is exactly 85 metres long. This does mean that Tasmania is far nearer than we all thought.
Until now, I had thought that the shortest on-land border between states was the border of the Australian Capital Territory and New South Wales, created in 1911 with a total length of 306 kilometres, not a long way when you think of it as a circumference but long enough if you wanted to build a politician-proof fence around it.
But wait. There is more. While looking for information about Boundary Islet and the Victorian border, I found another short one. HMAS Creswell is the naval base on Jervis Bay, seemingly in NSW but not so.
Jervis Bay was originally set aside as part of the Australian Capital Territory, so the ACT actually had two separate and distinct borders with NSW. There was a long-term plan to link Canberra and Jervis Bay by a dedicated railway, 173 kilometres long, so that the ACT had a port and access to the sea. Given its purpose I don't see why the ACT needed a coastal outlet. I assume, too, that the right-of-way would have been part of the ACT, making the border much, much longer.
Some NSW farmers would have had to cross the ACT to get to their bottom paddocks.
In 1989 the ACT gained self-government (it had been governing the rest of us for about sixty years) and Jervis Bay was seen as a legally-awkward bit which this became a little enclave under the authority of the Federal Minister for Territories. The Jervis Bay Territory covers only 70 square kilometres and its border with NSW is only 32 kilometres long, quite a bit more than the 85 metres of border on Boundary Islet.
This column covered the Black and Allan line not so very long ago. Between 1870 and 1872 surveyors Black and Allan surveyed the straight line that links Cape Howe and the Murray bas part of our border. That border was established in the Australian Constitutions Act of 1850, in the United Kingdom. The survey came out within a metre of its intended point. It ran from a spring which was held to be the source of the Murray through some very rugged terrain and came out at Conference Point at Cape Howe. This point had been agreed by Robert L. J. Ellery (Superintendent of the Victorian Geodetic Survey) and P. F. Adams (NSW Surveyor General). It was a point on the beach at Cape Howe.
One little border anomaly is that this line was not officially ratified until 2006, a hundred and thirty four years later. For the first 28 of those years Victoria and New South Wales were effectively separate countries without an exact border between them.
The border with NSW seems simply defined as the top of the southern bank of the Murray but that has led to some complicated legal manoeuvring. The river was a major 'highway' when the paddle steamers took wool, wheat and timber down the river and brought back all manner of goods. They traded with both sides of the river, of course, when the states charged different duties on goods.
There was one issue with Pental Island, in Victoria now by law, but claimed by NSW in an argument over which was the main course of the river. This dispute dates from 1859 and was only resolved by the Privy Council in 1872.
I'm getting a bit far away from Gippsland history at this point, but bear with me. I find some of this fascinating. For instance, there is a small part of our border which does not really exist. There is a little more than three kilometres of our border, up in the top west corner, where the Vic-NSW and SA-NSW borders are not aligned. The south side of the river is clearly 'ours' up to the 141st line of longitude but then for 3.6 kilometre the north bank does not belong to NSW but, probably, to SA, or can Victoria claim the full width of the river for those 3.6 kilometres?
Wade and White were the two surveyors who did most of the work, surveying in atrocious conditions. The survey was completed in 1850 but in 1849 White nearly died when he ran out of water. Some his bullocks and horses did die.
The border was surveyed using two different ways to measure the longitude – and the two did not agree. Wade and White averaged the discrepancy, meaning the border was a stepped line and not a straight one. It was supposed to meet the NSW border but missed.
Now, this bit is technical. Surveyors used chains to measure distance, but the world is a globe, so the lines of longitude get closer together as you get further southward. The chains they were using were not adjusted for this, so their intended 141st line of longitude was too far west.
Though the problem was suspected earlier it was not clearly established until 1883. The ownership of that 3.6 kilometre strip went to the High Court in 1911 but was not finally decided until a Privy Council ruling in 1914. Victoria won.
All that aside, I love the fact that we share a land border with the Island State.