The shocking act of vandalism was caught on video by two men flying a drone nearby.
One of the men flying the drone, David Kalas, says he confronted the eight men, who then claimed the rock formation was a safety hazard.
He told Inside Edition: "I confronted them and asked why are they doing this. One of the guys said: 'We are doing Oregon a favor,' saying it was a 'safety hazard.'"
Kalas also said that the man told him a friend of theirs was injuired at the rock recently but he didn't buy it.
Kalas told Inside Edition he is "pretty upset over this. It is a really beautiful landmark. It really upsets me that someone came there with the purpose of destroying something so beautiful."
The formation in Cape Kiwanda is known to locals as “Duckbill,” and was toppled to rubble after the men pushed it to the ground.
The area is off limits to visitors but over the years people have taken spectacular photos atop the Duckbill.
Authorities thought Duckbill had collapsed from natural erosion until they saw the video posted to Twitter.
The incident happened on August 29, but is only starting to come to national attention now.
Utah State Parks spokesman Chris Havel told the New York Daily News that the fine for destruction of a natural resource is $435. The Oregon State Police are working to identify the group and find out if any criminal wrongdoing occurred.
The case is similar to this incident in Utah in 2014 when two scoutmasters toppled an ancient rock formation that had stood for 200 million years in what is called Goblin Valley. They were fined $2,000 and served a year's probation.