|This item marks a mountain pass.|
|Used on these elements|
|Tools for this tag|
This item marks the highest point of a mountain way passing a crest.
In common usage the term "mountain pass" is ambiguous (see Wikipedia). The meaning can be a highway (road, footway, etc.) up and down a mountain or the saddle point. Unlike in common usage OpenStreetMap clearly differentiates between these two concepts. The notion introduced here is the highway.
A mountain_pass=yes tag should be the highest point of the way so it's a single node on that way. For the saddle point see natural=saddle. Be aware that highways don't always go exactly through the saddle point, so that the highest point on the highway and the saddle point can have different positions.
Applies to the "highest node" on a highway = motorway/secondary/footway/... (could be any appropriate "highway"):
Lots of passes are the border between two countries and therefore have names in (at least) two languages. These names should be tagged, e.g. name:it=Passo dello Stelvio and name:de=Stilfserjoch (but keep in addition a simple name=Passo dello Stelvio where possible, otherwise simple renderers may display no name at all). The corresponding language abbreviations can be found at ISO639-1 codes.
- wikipedia=* - A lot of the well-known passes have dedicated Wikipedia pages.