rock cairns in Yosemite National Park

Push these over, say rangers at Yosemite National Park

If you enjoy spending time in nature, you may have noticed stacks of rocks called rock cairns. These man-made structures can be miniature or enormous, but in any case, the balancing of the stones can look impressive. However, officials at Yosemite National Park warn visitors not to build these piles while on the trail. In fact, they recently encouraged people to topple rock cairns if they saw them around the park.

Knock Over Rocks at Yosemite National Park

There are several reasons Yosemite National Park rangers discourage the building of rock cairns. For one, visitors should respect nature when they are walking through wild spaces. Although rock cairns look pretty, their construction disrupts the vegetation and creatures around them. People may be careful not to uproot plants or litter to preserve these spaces, but cairns can result in similar disturbances to the surrounding ecosystem. For example, insects, reptiles, and microorganisms live under rocks, and people picking them and stacking them exposes these creatures and damages the habitats. [1]

Yosemite National Park sign

As Yosemite National Park stated on Instagram, “According to Leave No Trace ethics when we recreate in wilderness spaces, our goal is to leave no signs of our impact on the land and respect other creatures living in it.” They refer to the video where ranger pushes over a rock cairn as tall as a grown adult. “Unfortunately, this dramatically oversized cairn is a mark of human impact and is distracting in a wilderness setting.”

Additionally, many park rangers make rock cairns specifically for the purposes of safety and navigation for visitors. When guests build cairns of their own, they are not only disrupting nature, but they can also confuse others trying to follow specific trails. 

Read: Chile is Home to a Spectacular 1,700-Mile Trail, Connecting 17 National Parks

Don’t Knock ‘Em, Report ‘Em

However, although Yosemite National Park encourages people to stop building rock cairns and to dismantle them when they see them, not all park rangers agree with this approach. For instance, Arches and Canyonlands National Parks spokesperson Karen Garthwait pointed out that rock cairns are deliberately made to mark specific hiking trails. 

We ask that visitors do not disturb them, knock them down, add to them, or build their own, as that can lead to other visitors getting lost in the desert,” said Garthwait. However, she agreed with Yosemite National Park’s message to stop building them. “We also ask that visitors not create their own sculptures out of the rocks that they find and collect.”

Garthwait explains that Arches and Canyonlands have beautiful rock cairns made according to the Leave No Trace ethic and they are part of the parks’ appeal to visitors. But if guests notice any strange or suspicious-looking rock sculptures, they should report them to park officials, as they would report graffiti, instead of knocking them down themselves. The rangers will access the stacks and remove them safely if required. After all, it could be difficult to discern official rock cairns and unsolicited versions, but Garthwait has some advice on how to tell the difference.

Appropriately sized rocks are not uniformly distributed on all trails, and some trails require taller cairns if the desert terrain is uneven or has challenging sight lines,” she said. “That said, ranger-built cairns tend to have at least three levels of rocks, are built for stability, and are positioned so that you can see the next one at a linear distance from the previous one.” Plus, rock stacks grouped together like a garden or look particularly precarious, they are likely guest-made. But these “gardens” could have originated from a sanctioned cairn. “[That] is why it’s best not to knock anything down here, but just report it to a ranger,” said Garthwait. [2]

More About Rock Cairns

Not all rock cairns are built by park guests and rangers. In fact, archaeologists believe that some are hundreds of years old, miraculously withstanding weather and environmental changes. As a result, cairns become part of natural landscapes just like megaliths or earthen mounds built by indigenous people. The cairns are not just pretty structures. Their locations are often carefully chosen, and the construction may be culturally important. For instance, in Scotland, cairns are used to signify burials. These ancient cairns often have earth and vegetation growing around them; despite them being man-made, they have been re-accepted into the surrounding nature.

But archaeologists continuously debate about the origin and purpose of cairns made by Native Americans. “There are some archaeologists who think that everything is farm clearing,” said Lucianne Lavin, the director of research and collections at the Institute for American Indian Studies in Washington, Connecticut. As in, these stones are meaningless piles of rocks thrown together from an agricultural field. “There are other archaeologists, including myself, who realize that there are a diversity of features out there.[3]

Nevertheless, many cairns hold cultural significance in addition to looking exquisite. Therefore, it’s important for parks to preserve these sites. So the next time you hike through a national park, look out for these rock cairns. But remember, don’t build them. And if you’re Yosemite National Park, enjoy pushing over the piles made by other guests.

Keep Reading: 10 National Parks Everyone Should Visit At Least Once.


  1. “Yosemite’s message to visitors: Stop building, knock over rock cairns.NBC Bay Area. July 17, 2023.
  2. “Utah national parks say to leave rock cairns alone, despite Yosemite National Park PSA.ABC News. Derrick Fox. July 17, 2023
  3. “What Are Rock Cairns?” Live Science. Greg Uyeno. June 10, 2019