Charles Todd Obelisk - Renmark

How many of you ever wonder when you cross our state borders just how come that location is the actual correct state border crossing. Due to a major error when Victorian surveyors surveyed the South Australian/Victorian State Borders as far as the Murray River back in 1839, later surveys by South Australian surveyors found that an incorrect fixing of the meridian had caused the actual state border was in fact 3.2 kilometres too far west of its true location, which resulted in Victoria claiming a strip of land of 138,700 hectares that actually belonged to South Australia.

In 1868 to correct this critical error from the Murray River and north to the Queensland border, Charles Todd was given the task of accurately calculating the correct position of the 141st Meridian.

The following is taken from the display boards at what is now known as Todd's Obelisk that can be found north of Renmark off of the main Wentworth Road and the actual point where today's border survey started.

"This brick cairn was erected in 1868 by Charles Todd, South Australian Government Observer (astronomer) and Superintendent of Telegraphs, to mark the position of South Australia's border with New South Wales.

He set up a temporary observatory near here and, by astronomical observations and accurate time signals over the nearby telegraph line between Adelaide and Sydney, he calculated the position of the 141st Meridian of Longitude, the proclaimed boundary between the colonies of South Australia and New South Wales.

An incorrect fixing of the meridian in 1839, confirmed in the 1847-1850 survey from the coast to the River Murray, had caused the border to be up to 3.2 kilometres west of the correct position.

Charles Todd and the New South Wales Government Astronomer, George Smalley, met, accepted the determination, and had this obelisk erected beside the Wentworth, Road to mark the boundary, later surveyed to the Queensland border. Todd's position is accurate to about 100 metres.


While this allowed the border with New South Wales to be more accurately determined, it also raised the issue of the strip of land (138 700 hectares) in Victoria which should have been part of South Australia.

Over the next 43 years South Australia made various legal attempts to claim the land, but a High Court judgement in 1911 found in favour of the existing erroneous border.

An appeal in the Judicial Committee of the Privy Council was dismissed in 1914, and hence the dog leg in the South Australian border at the River Murray has remained to this day.

The marker is built of hand-made bricks, presumed to be from Wentworth, laid in a lime mortar and was described in Todd’s report as:-
A brick pyramid, 13 feet 6 inches high and 5 feet, 6 inches square at the base...having the words “PROVINCE BOUNDARY on the north and south faces: “NSW G.R. Smalley” on the east face, and “SA Charles Todd” on the west face...



It was originally 4.1 metres high but the top section has been lost and the square base buried by sand build-up. The section now visible stands only 2.1 metres high but the base is in good condition below ground level.

Repairs were carried out in 1911 when the position of the border was checked by G.F.Dodwell (SA Government astronomer).



An inscribed slate plaque dated 1911, on top of the obelisk, bears his name and those of Henry Jacob (surveyor) and F.J. Burgoyne (telegraph operator). Further repairs were undertaken in 1955 by J.B. Furwell."

If you are ever in the area, the drive out to this special location will let you see where this special place is and the Border Cairn that was erected in 1868.