08/27/2026
The history of our (very) old friend: Big Rock at Findley State Park
This is Findley State Park’s friend, BIG ROCK!
Big Rock has been a mainstay of our campground for generations. Countless photos of campers have been taken with Big Rock over the decades.
Big Rock grew up well to the north of Ohio in what would become Canada before moving to our area a very long time ago.
At least 11 to 14 thousand years ago, give or take a few thousand years.
We know that Big Rock is from Canada because it is made of Granite that was formed by molten rock called magma cooling underground in Canada.
Tens of thousands of years ago, the latest of the glaciers of the Ice Age moved over our area due to the incredible weight of snow and ice built up to 5 miles thick.
When ice accumulates to a thickness of about 160 feet, it starts to bend and move downhill. Since the glaciers that covered our area were MILES thick, everything was “downhill”.
As the glaciers moved south from Canada, the tremendous amounts of energy generated often broke of huge chunks of rock in its path.
These rocks, like Big Rock, were pushed and tumbled for tens of thousands of years, wearing down the edges and smoothing the surfaces.
Because there are no granite rock layers that are native to our area, and we know that the glaciers moved Big Rock and others to our area, Big Rock is considered a Glacial Erratic.
So, just how “BIG” is Big Rock?
I took some quick measurements and estimate Big Rock to be about 221 cubic feet of granite.
Most granite weighs about 165 pounds per cubic foot.
After all the math, I figure Big Rock weighs in at around 18.2 tons.
Naturalist Wiz
Share your photo of Big Rock in the comments.
We love to see your images of Big Rock.
Further reading:
https://www.clevelandmetroparks.com/parks/education/education-programs/virtual-learning/online-nature-center/activities/lessons/ice-age-ohio-hike #:~:text=In%20Ohio%2C%20many%20of%20our,and%20weighing%20over%202%2C000%20pounds
https://ohiodnr.gov/static/documents/geology/OGN_1984_n3Winter.pdf
https://ohiodnr.gov/discover-and-learn/safety-conservation/about-ODNR/geologic-survey/glacial-geology/evidence-of-glaciers
https://stoneyard.com/calculators/stone-slab-weight/