On October 24, 1867, the Danish government signed a treaty that the then-Danish West Indies would be transferred to the United States, pending ratification by both governments. Prior to this treaty, the West Indies’ residents were mostly Danish citizens. The Danish government also maintained a large military presence there until after the treaty was signed. If you have Danish ancestry, it is quite possible those ancestors spent some time in the Virgin Islands before traveling on to the United States or to other countries.
The St. Croix Avis newspaper published many articles about the activities and the departures of Danish citizens and others in its earlier days of publication. Your Danish ancestor(s) may be among those mentioned.
Public notices were often published in both English and Danish. If you see an interesting notice but can’t read the Danish, keep reading down the column. The notice would often be translated into English. Here’s an example:
You may search the St. Croix Avis newspaper by starting at: https://chroniclingamerica.loc.gov/lccn/sn84037526/.