Greenland Aside, Buying Foreign Land Used to Be Common

The last time the United States bought a foreign territory — through a monetary transaction and not just a signed treaty — was in 1917, when the Virgin Islands were acquired from Denmark.

More than 100 years later, President Donald Trump said he wanted to buy Greenland, the largest island in the world, from Denmark. Denmark has rejected that idea, but Trump is not the first president to attempt the purchase; Harry Truman tried in 1946, but Denmark wasn’t interested then, either.

In its 243-year history, the United States has purchased foreign land a number of times. Parts of present-day Arizona and New Mexico were bought from Mexico; Florida from Spain; and Alaska from Russia.

But that was centuries ago, during an era of exploration when powerful countries fought wars and negotiated treaties to claim land in the New World.

“That’s just not how it works anymore,” said Daniel Immerwahr, an associate professor of history at Northwestern University and the author of “How to Hide an Empire.”

At the turn of the 20th century, he said, there was a notion that the “frontier had come to an end” and there was little unclaimed land left.

“That was another way of saying territorial expansion would have to come at the cost of other powerful empires and not at the expense of indigenous peoples,” Immerwahr said.

Even as this land became more sparse, the desire to build an empire by accruing more territory contributed to both World War I and World War II.

“After World War II, the global map became far more static,” Immerwahr said. Countries found it “easier to project their influence over the world without having to annex huge swaths of territory,” he said.

Here are some of the most significant land purchases by the United States:

1803: Louisiana Purchase

The United States bought 828,000 square miles of land from France for $15 million, or the equivalent of $340 million today.

The territory extended across 15 modern states between the Mississippi River and the Rocky Mountains, including Arkansas, Colorado, Iowa, Kansas, Louisiana, Minnesota, Missouri, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas and Wyoming.

President Thomas Jefferson sent James Monroe to France to buy just New Orleans, but Napoleon Bonaparte offered the entire Louisiana territory.

1819: Florida

When the Adams-Onís Treaty was signed in 1819, Spain ceded West Florida and East Florida, which were two colonies that stretched across portions of what is now Alabama, Louisiana, Mississippi and the Florida Panhandle.

Both West and East Florida were British colonies during the American Revolutionary War. The Treaty of Paris of 1783 officially ended the war and returned both colonies to Spain.

In 1810, American settlers in West Florida declared independence from Spain. President James Madison and Congress used the rebellion as an opportunity to claim the region, asserting that the land was already part of the Louisiana Purchase.

John Quincy Adams, the secretary of state, began negotiations with Don Luis de Onís, the Spanish envoy to the United States, in 1815.

Under the Adams-Onís Treaty, the United States agreed to pay $5 million, the equivalent of $101 million today, for damage done by those who had rebelled. In addition, the western limits of the Louisiana Purchase were defined, and Spain surrendered its claims to the Pacific Northwest and was granted sovereignty over Texas.

The treaty was ratified in 1821.

1848: Mexican Cession

The Mexican-American War ended when President James Polk signed the Treaty of Guadalupe-Hidalgo in Mexico City in 1848. Mexico ceded 525,000 square miles of land for a lump sum of $15 million — the equivalent of $487 million today.

The ceded land included present-day California, Nevada and Utah, and portions of Arizona, Colorado, New Mexico and Wyoming.

The treaty granted United States citizenship automatically to Mexicans who remained in the region, and Mexican-Americans were also allowed to keep their property, according to the treaty.

1854: Gadsden Purchase

The United States paid Mexico $10 million (the equivalent of $305 million today) for nearly 30,000 thousand square miles that encompassed parts of present-day Arizona and New Mexico, according to the United States Office of the Historian.

Though the Mexican-American War had officially ended in 1848, tensions between the Mexican and U.S. governments persisted.

Both countries claimed the Mesilla Valley, which stretches from southern New Mexico to western Texas.

President Franklin Pierce sent James Gadsden, the U.S. minister to Mexico, to negotiate with Antonio de Santa Anna, the Mexican president. The new treaty established the southern border of the United States.

1867: Alaska

The United States bought nearly 600,000 square miles of land from Russia for $7.2 million, or the equivalent of $125 million today.

The purchase marked the end of Russian efforts to expand in North America. Russian czar Peter the Great began exploring the region in 1725; however, the population of permanent Russian settlers in Alaska never exceeded 400, according to the U.S. Office of the Historian.

Though interested in the region’s natural resources, Russia lacked the finances to support major settlements. After facing defeat in the Crimean War, Russia offered to sell Alaska in 1859.

The deal was delayed by the American Civil War, but President Andrew Johnson eventually signed the treaty in 1867. Alaska didn’t become a state until 1959.

1898: Philippine Islands

The Treaty of Paris of 1898 ended the Spanish-American War. Spain ceded the Philippines, its colony for more than three centuries, to the United States.

By the treaty, Cuba gained its independence and Spain also ceded Guam and Puerto Rico to the United States.

The United States paid $20 million (the equivalent of $618 million today) for the Philippines.

The next year, however, Filipino nationalists rebelled against U.S. forces, sparking the Philippine-American War. Led by Emilio Aguinaldo, the nationalists sought independence from all colonial rulers.

The war lasted three years, and the United States granted the archipelago independence in 1946.

1917: Virgin Islands

The islands, which span more than 130 square miles, were bought from Denmark for $25 million, or the equivalent of $501 million today.

The islands include Saint Croix, Saint John, Saint Thomas and many other minor islands.

The United States had been trying since 1867 to expand its influence into the Caribbean by acquiring the Danish West Indies, as they were then known. President Woodrow Wilson signed a treaty in 1917 and the Virgin Islands were formally transferred.