Use {{location|DK}} to tag expeditions that took place in Denmark. It will add Category:Meetup in Denmark to the expedition.
Using ISO 3166-2 abbreviations, you may also tag the region that the expedition took place in. Greenland and the Faroe Islands are ISO 3166 areas in their own right, use GL and FO for them, respectively.
If the category link appears red, do not worry and create the category. Make sure that it is included in the appropriate parent category, for instance, Category:Meetup in Syddanmark is a subcategory of Category:Meetup in Denmark. The subcategories should be sorted in by their respective code.
Examples
{{location|DK}}: Denmark{{location|DK|83}}: Syddanmark
