Okotoks Big Rock

Athabasca Glacier

Okotoks erratic, The Big Rock

To locals it’s The Okotoks Big Rock, but the name doesn’t convey its significance. This glacial erratic is a designated Provincial Historic Resource. Obviously, this is a really big rock, 16,500 tonnes (18,200 tons) to be precise. It’s 41 by 18 metres (135 by 60 feet) and is 9 meters (30 feet) high. And it’s sitting out on the prairie.

Let’s start with a bit of history, to understand what is it and how it got here.  Big Rock’s origin is in the Rock Mountains. A massive landslide occurred near Mount Athabasca about 30,000 years ago. This is 280 kilometers (175 miles) as the crow flies to the north east from its current location. Distance traveled was far more because the route was not direct.

mapiong showing distance from origin to final resting place of Okotoks Erratic

The landslide deposited millions of tonnes of rock on top of the Athabasca Glacier. Glaciers “flow,” and this flow is certainly much slower than a river of water. Over the ages this pile of rock moved eastward and then down the eastern edge of the Rocky Mountains. Rocks were deposited along the route. The Foothills Erratic Train, as it’s known, runs 644 kilometers (400 miles) from Jasper National Park to northern Montana. Pieces ranged from gravel to enormous boulders. The largest of these is the Okotoks Erratic, our Big Rock.

 Indigenous Connections

The Blackfoot word for rock is “okatok”.and this is the origin of our town’s name Big Rock has cultural significance for the Indigenous people in the area. Here is a Blackfoot legend:

“One hot summer day, Napi, the supernatural trickster of the Blackfoot peoples, rested on the rock because the day was warm and he was tired. He spread his robe on the rock, telling the rock to keep the robe in return for letting Napi rest there. Suddenly, the weather changed and Napi became cold as the wind whistled and the rain fell. Napi asked the rock to return his robe, but the rock refused. Napi got mad and just took the clothing. As he strolled away, he heard a loud noise and turning, he saw the rock was rolling after him. Napi ran for his life. The deer, the bison and the pronghorn sheep were Napi’s friends, and they tried to stop the rock by running in front of it. The rock rolled over them. Napi’s last chance was to call on the bats for help. Fortunately, they did better than their hoofed neighbours did, and by diving at the rock and colliding with it, one of them finally hit the rock just right and it broke into two pieces.” Credit: Alberta Culture and Tourism https://www.alberta.ca/okotoks-erratic-big-rock.aspx


CyArk is a nonprofit whose mission is to “digitally record, archive and share the world’s most significant cultural heritage and ensure these places continue to inspire wonder and curiosity for decades to come”. They produce high quality 3-D digital scans of archaeological and cultural heritage sites. There are only three sites in Canada that have been preserved in this way. The Big Rock is one of them. CyArk partnered with the Government of Alberta and SarPoint Enginerring. The scanning was done in September of 2013. Visit their website here: https://www.cyark.org/projects/okotoks-erratic/overview to view.

Trip Advisor list The Big Rock as the Number One thing to do in the Okotoks area. When you are visiting the area we hope you now have some understanding. And it’s why there are a number of businesses that use Big Rock in their name. Make it part of family day trip. For other day trip ideas click here.