Wikivoyage:Extraregion pages describe destination regions which overlap existing boundaries, such as the Quad Cities (divided between two US states) or the North American Great Lakes (divided between two countries). These run parallel to the existing breadcrumb hierarchy, as a means of handling special cases where overlapping regions are known by a number of different names or a destination crosses standard region boundaries (such as continents, countries, states or provinces).

The parent region for {{isPartOf}} tags should be at the lowest level which still includes everything in the extra region - in the case of a destination which crosses an international boundary, this could be a continent.

Since these regions are extra-hierarchical, they should generally not have any subregions or destinations below them which use them in their breadcrumb trail the parent region in the real hierarchy should be used instead. When applying this template, it's a good idea to check the destinations listed and change them to the appropriate hierarchical parent.

Once applied, if there is a corresponding hierarchy category, the page will be added to Category:Extra regions with categories for maintenance. Rare exceptions can be made when the child article is itself a valid extraregion, such as the case where the Great Lakes includes Lake Ontario. For such exceptions, add the subregion=yes attribute to the template call, which will prevent the maintenance category from being applied.