OpenStreetMap: Admin_level for All Countries

Tag:boundary=administrative

The boundary=administrative tag is used on relations that define an administrative area − territories recognised by governments for administrative purposes. This works rather like multipolygon – the relation consists of one or more boundary ways that must make up a closed area.

Administrative boundaries range from large groups of nation-states down to small administrative districts. An indication of their size/level of importance is given by the tag admin_level=* which takes a value from 1 to 11. Many administrative boundaries are currently also tagged with place=*.

It is recommended that all boundary areas are represented by type=boundary relations. Their border ways may be left completely untagged, with only outer and inner defined as appropriate.

Locating the administrative boundary

Administrative boundary in case of disputes

• OSM follows On the Ground Rule. Boundaries recorded in OpenStreetMap are the ones that are the most widely internationally recognised and that best meet realities on the ground, generally meaning physical control.
• OSM community attempts to map world as it exists, not as it should exist.
• Boundaries may overlap in areas of joint administration or contested territories.

Administrative boundary at sea

Administrative boundaries should only include land, internal waters, and territorial sea (often 12 nautical miles). They should never contain international waters.

Administrative boundary formed by a river or road

Avoid gluing boundaries to rivers or roads unless the boundary is legally defined by the dynamic current course of the river. Glued nodes cause accidental edits when natural features change.

Super-national administrations

Organizations like the United Nations, European Union, or ASEAN are not mapped with admin_level=1 on OpenStreetMap.

National and Sub-national levels

• admin_level=2: Independent countries adhering to ISO-3166-1 standard.
• admin_level=3 to 11: Sub-national administrative divisions (states, provinces, districts, municipalities, villages).