The two latest purchases actually involved Denmark.

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During his first term as president, Donald Trump floated the idea of making Greenland part of the U.S.

At the time, it was laughed at by pretty much the rest of the world. However, when the U.S. conducted a military operation in Venezuela to take the dictator Nicolás Maduro captive, people began taking Trump’s remarks about Greenland very seriously, especially when he revived the idea just days after the Venezuelan operation.

According to Donald Trump, Greenland is crucial to the national defense of the U.S., and he has threatened a number of NATO allies with tariffs starting February 1 if a deal on full U.S. control of Greenland is not reached by then.

The tariffs will increase by June 1 if a deal has not been made.

Easy way or hard way

Trump has said that Greenland will become part of the U.S., and that it can be done the “easy way” or the “hard way,” leading many to fear potential military action to achieve the goal.

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During his first term, however, Donald Trump suggested that the U.S. buy Greenland from Denmark (Greenland is part of the Kingdom of Denmark)—an idea that was shut down immediately by both Greenland and Denmark, with the argument that Greenland belongs to the Greenlandic people and that you cannot buy a country like that.

But the U.S. has a history of buying territory—and the last two purchases actually involved Danes as the other party to the deal.

Note: We have not included territory annexed by the U.S. in this. We have solely focused on territory purchased.

Water Island and Danish Virgin Islands

In 1944, the U.S. bought Water Island (Vand Ø in Danish) from a private shipping company based in Denmark called the East Asiatic Company.

It is a minor island in the United States Virgin Islands in the Caribbean Sea, and the U.S. paid $10,000 for the nearly 500-acre island.

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Nearly thirty years before this, the U.S. bought the Virgin Islands from—you guessed it—Denmark. At the time, they were known as the Danish West Indies, and the U.S. paid $25 million for the islands (equivalent to approximately $614 million in 2024).

The Louisiana Purchase and the Alaska Purchase

The two most famous territorial purchases are probably the Louisiana Purchase in 1803, when the newly created United States (known as the Thirteen States at the time) acquired 828,000 sq mi (2,140,000 km²) of territory, much of which is part of the central U.S. today.

The price tag was $15 million, which is equivalent to roughly $340–371 million in 2024 terms.

In 1867, the U.S. bought Alaska from Russia for $7.2 million, which is equivalent to over $130 million in 2024 terms.

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