The United States purchased the US Virgin Islands from Denmark in 1917. The transfer was formalized on March 31, 1917, after the U.S. paid $25 million in gold for what were then called the Danish West Indies.
• The islands of St. Thomas, St. John, and St. Croix had been Danish colonies since the 17th and 18th centuries.
• Denmark agreed to sell them to the U.S. under the Treaty of the Danish West Indies, signed in 1916 and enacted in 1917.
• The U.S. wanted the islands for strategic military and naval reasons, especially during World War I.
• Denmark, facing high costs and declining economic value from the islands, agreed to the sale.
I never knew this from my history education. I've been to all three US Virgin islands and they are wonderful. We had two different vacations to Frederiksted, St. Croix. We've snorkeled in the National Park at Hawksnest Bay in St. John and St. Thomas is a cruise port that we've been to more times than I can remember. It's paradise in the Caribbean. Maybe Denmark should ask for it back!