Cairns are small stacks of rocks used to mark trails. These can be especially useful above the tree line where other trail blazes would be inappropriate or unsightly.

This answer discourages their use in some circumstances as their use creates paths where there previously were none.

In which situations/circumstances/settings is making a cairn, or multiple cairns, appropriate?

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    IMO far more cairns get built than should be built. I knock down a lot of them, because they alter the landscape unnecessarily. This is probably related to the fact that so many people have poor map reading skills, and so little experience with off-trail travel, so that they need constant reassurance.
    – user2169
    Commented Mar 2, 2016 at 15:45
  • 1
    Many cairns are akin to graffiti. Someone just has to express himself. These are probably the same people who do "exterior decoration" on their backcountry camping spots -- highly arranged logs, stone benches and stone side tables. IMO, they are afraid of wilderness and should take up bowling. (I've had a bad day.)
    – ab2
    Commented Mar 2, 2016 at 21:39
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    Leave no Trace ethics states that cairns should not be constructed, and that you should use a map and compass instead. lnt.org/sites/default/files/Cairns_Leave%20No%20Trace_FINAL.pdf
    – ShemSeger
    Commented Mar 2, 2016 at 21:58
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    @BenCrowell: cairn police? I'd exchange in an heartbeat a cairn builder for every one that seems to not be able to pick up their garbage Commented Mar 3, 2016 at 22:22

3 Answers 3


On designated trails that are infrequently traveled and maintained, using them to mark a faint or overgrown section of trail, the point a trail passes under a large downed tree, a switchback, a trail junction, or a creek crossing, where the tread of the trail itself is not visually clear ahead, is generally acceptable and helps keep people on the actual trail.

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    ...also before going into battle.
    – DudeOnRock
    Commented Mar 2, 2016 at 7:47
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    Often times I see cairns in boulder fields where its nearly impossible to make an actual trail, yet the trail is marked on a map. Often times in mountaineering you'll find cairns to help navigate you up a certain route. Again with the massive rocks is very difficult to outline the route otherwise.
    – tsturzl
    Commented Mar 2, 2016 at 20:53
  • I agree with the boulder field comment, but think that the examples posted in the Answer are often easily dealt with by scouting ahead.
    – ab2
    Commented Mar 2, 2016 at 21:31
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    Not everyone has the same level of navigational skills or knowledge about the trail route. There is an infrequently used trail near me which passes through a grassy field and often disappears under this grass, leading to half a dozen braided trails as people wander around, looking for the trail. After building cairns along the official route, I returned 6 months later and found that the side trails had disappeared and the actual trail was properly beaten back in and visible. Commented Mar 2, 2016 at 22:09
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    Another time a cairn may be advisable is when there is something else which looks like a trail heading in a different direction. There is a ridgetop trail which transitions into a sideslope trail at the same point an old fireline continues steeply up the ridge, and people would get lost on the fireline, missing the much easier trail. A series of large cairns here solved this problem by effectively distracting people from seeing the wide fireline and bringing them far enough towards the actual trail they could see it ahead. Commented Mar 3, 2016 at 14:39

What are the issues?

There are two issues here: the siting of official navigation cairns by whoever is responsible for maintaining the trail, and the building of unofficial cairns by visitors.

Official cairns

For official cairns, attitudes to waymarking vary widely in different countries based on local traditions and conditions. The locals will build and maintain any cairns that are required, and their decisions should be respected.

In the UK we are broadly influenced by "Unna's Rules", which emphasise that land should be left in its natural state so far as possible and that walkers should rely on their navigation skills. Even official cairns are kept to a minimum.

Unofficial cairns

For unofficial cairns, it's not the role of visitors to alter the landscape. In the context of Europe, or of highly trafficked trails anywhere, I can't think of any valid reason for a visitor to build a cairn.

These unofficial cairns are becoming a genuine menace here in the UK. In heavily used areas like Ben Nevis and the Lakes, local rangers and volunteers have to remove literally hundreds of cairns a year. They damage the landscape and can be misleading if not well sited. The new fad for stone-balancing isn't helping either - it's important that people dismantle their creations after they've been photographed.

Please leave no trace!

So to summarise, if you're part of a ranger service or club maintaining a trail, it's more than likely that you will be following well established local guidelines honed through generations of experience. If you are just visiting, please leave well alone and enjoy the landscape as it is.

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    I don't think Leave No Trace really applies in this setting. I think in terms of LNT that making a Cairn to keep people on the trail is more ethical. LNT states to travel on steady ground, its best to stay on trail, and a cairn will help you do that. In the case that people are making useless cairns, then that's a different story, but outside the context of the question.
    – tsturzl
    Commented Mar 2, 2016 at 20:50
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    In addition navigation skills aren't completely accurate, it usually relies on visual queues from the landscape(rivers, rock structures, topo, or the trail itself). A cairn would likely be better aid to keep someone on a designated trail than a bearing from a compass, which is often just a straight line.
    – tsturzl
    Commented Mar 2, 2016 at 20:58
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    This is fairly subjective, and depends on the location and amount of use. Certainly, cairn building can be a problem in highly visited areas, and quickly become a nuisance when it's done unnecessarily. But in remote Wilderness areas that get a small number of visitors on their official trails, the users are generally the only people keeping those trails in existence by using them and the construction of cairns to help the next user find their way. I've found otherwise lost trails thanks primarily to old cairns at key points. Actual authorized maintenance is preferable, but not always possible. Commented Mar 2, 2016 at 22:13
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    Please note that I specifically mentioned that I'm talking about Europe and about highly trafficked trails. In this context unofficial cairns are a major issue. You guys are talking about rare edge-cases in remote wilderness that don't really apply in areas like the UK, the Alps and the Pyrenees, while I'm talking about everyday experience that affects almost everyone here. In my view Leave No Trace is highly relevant in this context - everywhere I go in Europe unofficial cairns are becoming a blight. The locals are curating the landscape for us, and I'm happy to trust their judgement. Commented Mar 2, 2016 at 23:26
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    @tsturzl: LNT states to travel on steady ground, its best to stay on trail, and a cairn will help you do that. I think it's more complicated than that. For one thing, there may be no trail. On a cross-country route that has no trail but that is used by quite a few people, the landscape may actually be less damaged if different people take different routes, so that no track is formed.
    – user2169
    Commented Mar 3, 2016 at 2:34

I would generally agree with the "as few as possible approach", but would add that if it is a question of safety or avoiding lots of time wasted (which in turn may morph into a safety issue), then I think markers can be helpful.

But I don't think it should be exaggerated - markers can be used instead of cairns.

For example in Vistasvaggi (Vistas Valley) in North Sweden, there are fairly inconspicuous markers in the form of two half buried brick-sized red-brown rocks close to each other. I didn't understand they were markers until I had seen a few.

Of course you can argue it is hard to get lost even in a wide valley and it certainly is at large scale, but I found it helpful to get the detail right when going over soggy ground, tired and damp.

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