Australia’s longest river is entirely New South Wales water
The Murray River runs 2,508 kilometres from the Australian Alps across inland plains—Australia’s longest stream, with five of the next six longest rivers among its tributaries. Oddly, until South Australia, the entire channel and bed sit in New South Wales because the Victoria border hugs the top of the southern bank.
Rising on the Alps’ western flank, the Murray forms the NSW–Victoria line, then swings south at Morgan for its last 315 kilometres, passing through Lake Alexandrina before reaching the Southern Ocean at Encounter Bay. Together with the Darling it builds a 3,750-kilometre system whose basin covers about a seventh of Australia, yet it carries only a small share of the water of similar-length rivers elsewhere. It has run completely dry three times since records began, and by 2010 received just 58 percent of its natural flow.
The border quirk has real consequences: in 1980 the High Court had to decide which state had jurisdiction over the unlawful death of a man fishing on the Victorian bank. Further west, an 1840s surveying error of 3.72 kilometres left an 11-kilometre stretch where the Victoria–South Australia line runs midstream, sparking a long boundary dispute.
From roughly 2.5 million until half a million years before present, the river emptied into Lake Bungunnia, a freshwater sea of up to 33,000 square kilometres that drained around 600,000 years ago as the basin dried. About 25,000 years ago movement on the Cadell Fault lifted a ridge 8 to 12 metres high across the Murray's path, splitting the flow around it and creating the flood-prone country where the famous Barmah red gum forests grew; the narrow Barmah Choke still limits how much water can pass.
The Ngarrindjeri of Lake Alexandrina tell how the ancestor Ngurunderi carved the river while chasing Pondi, a giant Murray cod. Hamilton Hume and William Hovell reached it at present-day Albury in 1824, and in 1830 Charles Sturt, arriving via the Murrumbidgee, named it for Sir George Murray without realising it was Hume's river. Dredges have worked around the clock at the Murray Mouth since the early 2000s to stop it silting shut.
Source: Murray River
