top of page

The Macdonald Lake Structure

An underwater photo of a stone structure. Because it was taken with an underwater camera with night vision, the photo is tinted green. We can see one very large rock positioned on top of two smaller rocks.

Macdonald Lake is a lake situated in the Haliburton Forest and Wildlife Reserve Ltd, in Haliburton County, Ontario, Canada. It consists of 300 square kilometers (120 square miles) of forests, lakes, and creeks. Macdonald Lake is one of these lakes, and in 2005 a submarine project taking place in the lake discovered an ancient stone structure in the depths of the lake that has been dated back to some time between 9000-7000 BCE. This would mean that the structure was built around the time of the Last Glacial Period (LGP), or Ice Age.

The structure was found at a depth of around 40 feet (12 meters), and at first, it was thought that they were a natural formation; a so-called 'perched erratic'. These perched, or glacial, erratics are rocks that have been moved and deposited via glacial movements, often being deposited in areas not native to the rocks. Rocks deposited in this way can be used to trace the paths that prehistoric glaciers took. However, when the rock structure was examined in greater detail, the scientists and geologists studying it came to the conclusion that it was in fact man-made.

The structure consists of one 1,000lb - 453kg - elongated rock, almost completely level, that rests on seven baseball-sized stones. All of this sits on a slab, estimated to be several thousand lbs in weight, on top of a ledge. It has straight edges and a lack of roundness, both of which both geologists and archeologists would have expected to have happened if the rocks had been moved by glaciers.

A statistician was consulted, to try to calculate the probability of this structure having been formed by natural movements of rocks. The statistician explained that four rocks falling on each other to form a structure such as this would be extremely unlikely. Seven rocks doing the same - falling together in just the right way to form a structure - would have been virtually impossible.

An underwater archeologist was also called in to study the structure. The archeologist discovered evidence of three shims, or stabilising wedges, which provided absolute evidence that the structure was man-made, and not a random fluke of nature and probability.

Several questions still remain about the structure, however. What was the structure's purpose? When exactly was it erected, and by whom? Unfortunately, a thick layer of silt covers all of the vertical surfaces, which made it impossible to find any evidence of tools, decorative images, or anything else that could provide clues as to its origins or creators.

A pair of black and white photos showing the Macdonald Lake structure from different angles. The one on the left shows the elongated rock balancing on two of the smaller rocks; the second is a close-up of the smaller rocks.

Between 9000 and 7000 BCE there was an extremely severe drought across a large part of Eastern North America. During this drought, water levels in the Great Lakes were known to be up to 50 meters lower than their normal levels. Island lakes like Macdonald Lake, fed by spring melt and summer rain, would likewise be several dozen feet lower as well. This, at least, would go some way to explaining how the structure came to be in Macdonald Lake, although it still does not explain how the rocks were moved to their positions, or what its purpose was. Possible explanations for its purpose look at how Macdonald Lake is home to an ancient, glacial relist - a lake trout that is one of the oldest and purest strains of trout in the world. It came to reside in Macdonald Lake after it was stranded there in the last Ice Age, over 10,000 years ago. The structure could have been erected because of that, to signify a fishing source, celebration, or monument to it.

Others have noted the similarities between the structure and an inuksuk - a type of stone landmark or cairn built by the Inuit, Iñupiat, Kalaallit, and Yupi peoples of the Arctic region of North America. Traditionally, inuksuit have been used for navigation, as reference points, markers for travel routes, fishing places, camps, hunting grounds, or places of veneration. The word inuksuk means "that which acts in the capacity of a human".

Whatever the reason for the structure's construction, or how it came to be 40 feet deep in Macdonald Lake, its existence is proof that ancient cultures that existed around the time of the last Ice Age were far more advanced than we had previously realised.


"Remote Ontario Lake Reveals Mysterious Ancient Structure" (Cision)

"Mysterious Ancient Underwater Structure Beneath MacDonald Lake Reveals Traces Of A Lost Civilization In Ontario" (Ancient Pages)

"Ancient Stone Structure Found in Ontario Lake" (The Megalithic Portal)

"10,000-year-old underwater structures at Lake MacDonald point to a long-lost civilization" (Ancient Code)

Inuksuk (Wikipedia)

bottom of page