|boundary = historic|
|A historic administrative boundary|
|Used on these elements|
|Status: in use|
|Tools for this tag|
A historic administrative boundary. Subdivisions of areas/territories/jurisdictions recognised by governments or other organisations for administrative purposes.
Note that though historic objects should not be mapped as it is outside of scope of OSM (unlike projects like Open Historical Map), it makes sense to keep for some time old boundaries after administrative division change as form of note to make clear that there was a recent change of borders in a given location.
A historic administrative boundaries range from large groups of nation states right down to small administrative districts and suburbs, with an indication of this size/level of importance, given by the combo tag admin_level=* which takes a value from 1 to 10 as described below.
The boundary=historic tag is used on ways . It may also (or instead) be used on a relation grouping several ways.
See comparison of life cycle concepts for more possibilities.
admin_level=1 to 10 describes the hierarchy of different historic administrative borders.