Not sure about the Åland Islands, but at least Faroe and Greenland have a different visa regime than Denmark (they are both not in Schengen. Also Danish citizen

Not sure about the Åland Islands, but at least Faroe and Greenland have a different visa regime than Denmark (they are both not in Schengen. Also Danish citizen residing e.g. in the Faroe are not seen as Schengen citizen, or something like that). Generally a hard edge case are all those autonomous or semiautonomous territories. Like all the islands of UK and France (some French territories are part of the EU, some are not). It's often a lot harder to get info on the visa requirements for those.