A neat pile of stones appears where the path becomes difficult to follow. It is tempting to treat it as an instruction. Before changing direction, ask whether the land manager actually uses cairns to mark that route.
The US National Park Service’s guide to rock cairns explains that practices differ between parks. Some maintain navigational cairns; others warn visitors not to rely on stone piles. The local system matters more than the shape of one stack.
Learn the route’s marking system before setting out
Read the current official route description and notices. Find out whether you should expect painted marks, posts, cairns or another system, and carry appropriate navigation tools you know how to use. A photograph of a cairn from someone else’s walk is not a substitute for that preparation.
At an uncertain junction, pause in a safe place and compare your location with the route information. Do not keep following piles merely because another appears farther away. If the route cannot be established safely, use your planned return or assistance options rather than improvising a shortcut.
Leave the stones as you find them
Do not add a personal cairn to celebrate a viewpoint or improve what seems to be a confusing section. An unofficial marker may mislead the next walker. Do not dismantle an existing pile either; it may be maintained for a purpose you have not recognised.
If a marker appears damaged or misleading, note its location safely and report the concern to the responsible land manager. Describe what you observed without claiming to know who placed it there.
For a walking group, agree that navigation decisions will be checked together at uncertain points. One confident person moving ahead can make an unverified guess look like established knowledge.
A cairn can be useful within a known marking system. Its usefulness comes from that context, not from the simple fact that somebody stacked the stones.