From OpenStreetMap Wiki
These are used to describe administrative and other boundaries. See the page Boundaries for an introduction on its usage.
|boundary||administrative||An administrative boundary. Subdivisions of areas/territories/jurisdictions recognised by governments or other organisations for administrative purposes. These range from large groups of nation states right down to small administrative districts and suburbs, as indicated by the 'admin_level=*' combo tag.|
|boundary||historic||Historic administrative boundaries, along with start_date=* and end_date=* to specify dates of effect. Requires an additional admin_level=*.|
|boundary||national_park||Area of outstanding natural beauty, set aside for conservation and for recreation (Other languages).|
|boundary||postal_code||Postal code boundaries|
|boundary||religious_administration||An religious administrative boundary. Requires an additional admin_level=*. See: Talk:Key:boundary#Religious authority boundaries.|
|boundary||protected_area||Protected areas, such as for national-parks, water protection areas or indigenous areas.|
|boundary||user defined||All commonly used values according to Taginfo|
|admin_level||(number)||Applies to boundary=administrative and is usually in the range 1 to 10, except for Germany where it might be 11 – see boundary.|
|border_type||*||To distinguish between types of boundary where admin_level isn't enough. Used in several different ways e.g in maritime contexts.|
|start_date||(date)||Useful if there are competing historic boundaries or the boundary is very recent (or if it will become effective in a near future) and if keeping previous boundaries are still needed separately (including for statistical maps that are based on older boundaries).|
|end_date||(date)||Should be specified for all historic boundaries, or boundaries that will soon become ineffective (and possibly replaced by others) e.g. for administrative territorial subdivision reforms.|
|fire_boundary||yes||Tag fire_boundary used to mark the boundaries of the areas of fire brigades out within the project Karta01.|
This table is a wiki template with a default description in English. Editable here.