See These Rock Piles? Knock Them Down, Says Yosemite

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Kelsey is a freelance writer based in Southern Virginia. She enjoys traveling with her family to destinations from national parks to amusement parks and loves sharing tips and stories from along the way.

When it comes to cairns, national parks are asking visitors to get their facts straight. 

What are cairns? Is it ok to build them? What should hikers do if they spot a cairn on a trail? Learn the answers to these questions and prepare for a hiking experience that is safe, rewarding, and leaves the wilderness just as you found it.

What Is a Cairn? 

Cairns are small rock piles that can be placed to help guide hikers. These markers can help delineate a new or challenging trail, but not every national park uses them. 

Stone Rock Cairn
Photo Credit: Deposit Photos.

According to National Park Services, some parks, like Acadia, El Malpais, and Hawaii Volcanoes, use cairns that are carefully designed and maintained by park rangers to keep hikers on the correct path. 

Others, like Capitol Reef National Park, don’t use cairns. Markers created by visitors in these parks can confuse hikers who think they should follow them. Before venturing out, always research the park where you are hiking and learn whether or not cairns are maintained by park staff. 

Unauthorized Cairns? Knock Them Down! 

In a recent post to Facebook, rangers at Yosemite National Park encouraged visitors not to create unauthorized cairns and to knock down any visitor-created rock piles that they spot. 

Below is the video of a Wilderness Restoration Ranger knocking down a tall stack of rocks in Yosemite National Park. 


While this might seem dramatic, the fault really lies with the hiker who erected this huge stone pile in a natural setting. The cairn shown here is quite tall and could injure hikers or wildlife if it fell over. 

As the NPS pointed out in their post, “This dramatically oversized cairn is a mark of human impact and is distracting in a wilderness setting.” They add that stacking rocks in this way can disturb small reptiles and insects that normally live on the underside of these rocks. 

Building unauthorized cairns also violates Leave No Trace ethics. Removing rocks can make the soil more prone to erosion, disturb vegetation, and upset fragile micro-ecosystems. 

It’s also important not to add to or disturb authorized cairns. These markers are carefully designed to help hikers navigate, and tampering with them can cause other park visitors to become lost. 

Know Before You Go

We’ll admit that it can be confusing to determine when cairns should be observed and when they can’t be trusted or should even be knocked down. 

To help you navigate safely, here are a few top tips: 

  • Before hiking, research whether your destination utilizes cairns.
  • Never create your own cairns and don’t add to or tamper with existing ones. 
  • When in doubt, ask a park ranger about the signage used at your hiking destination. 
  • Always adhere to Leave No Trace ethics. 

With these guidelines in mind, all hikers can enjoy national parks while leaving the park just as beautiful and untouched as it was before the hike took place. 

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