History’s 8 biggest land deals: how the US more than doubled in size – and why it agreed to leave Greenland alone

From the Louisiana Purchase to the sale of Manhattan Island, Piers Mucklejohn explores eight moments in history when vast swathes of land changed hands for money

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Published: January 21, 2026 at 5:15 PM

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The Alaska Purchase (1867)

When the US banked an unexpectedly amazing bargain from Russia

In 1867, the Russian empire made the US an offer that it could hardly refuse. Still reeling from crushing defeat in the Crimean War in 1856 and fearing that the British might seize Alaska to extend their power in the Pacific, it was desperate to offload that territory.

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At the end of March, less than a month after Russian envoy Eduard de Stoeckl began negotiations with US secretary of state William Seward, the sale was made. Seward’s expansionist desire to extend US territory, especially in the Pacific, spurred him on to negotiate all night. The transfer of Alaska was agreed at 4am on 30 March – 586,000 square miles sold for just 2 cents per acre, a total of $7.2m (equivalent to around $155m today).

Contrary to popular belief, the purchase was generally supported by the public, though scornful commentary in some newspapers heaped criticism on “Seward’s Folly”.

“We simply obtain by the treaty the nominal possession of impassable deserts of snow,” the New York Daily Tribune complained of the territory, much of which lies within the Arctic Circle. “We may make a treaty with Russia but we can not make a treaty with the North Wind, or the Snow King.”

Beneath the snow, though, gold was discovered in the 1890s. There was oil, too – all in all, a hidden treasure trove of natural resources. The Alaska Purchase proved to be one of history’s most serendipitous land deals.

A black and white photograph of a group of five men standing around a long, rectangular table

The purchase of the Danish West Indies is completed in 1917 with the transfer of payment. The US deemed these Caribbean islands vital to its natural security in the face of German U-boat threats

The US purchases the Danish West Indies (1917)

This Caribbean deal took 50 years to finalise – and involved the US leaving Greenland to Denmark

Before the US Virgin Islands took that name, they were owned by Denmark, which governed them from 4,500 miles away across the Atlantic – more than four times farther than the US.

The Caribbean island of Saint Thomas was claimed in 1672 by the Danish West India-Guinea Company, which annexed Saint John in 1718, then bought Saint Croix from France in 1733. They were all taken over by the Danish crown two decades later.

In the aftermath of the American Civil War, President Andrew Johnson came close to securing two of the islands, aiming to establish a refuelling and repair station for the US navy and bolster American dominance in the region. When the treaty was put before the US senate in 1868, though, it was never voted on.

Come the First World War, the strategic importance of the islands to US national security was thrust into the spotlight. There were fears that Germany might use the Danish West Indies as a base from which to launch U-boats.

Washington believed that possessing these islands was necessary to secure the Caribbean and protect the newly opened Panama Canal. And Secretary of state Robert Lansing made it clear to Denmark that the US might seize the islands by force.

So in 1917, Denmark ceded the three islands to the US for $25m in gold (equivalent to around $630m today). Notably, as part of the treaty, the US declared that it would “not object to the Danish Government extending their political and economic interests to the whole of Greenland”. Four years later, Denmark formally declared their sovereignty over it.

A black and white illustration showing three men, two standing and one sat around a square table, looking at a large map

US envoys James Monroe and Robert R Livingston negotiate the 1803 purchase of the Louisiana Territory from France with Charles Maurice de Talleyrand. With France desperate for funds, the Americans were able to broker a bargain price (Image by Getty Images)

The Louisiana Purchase (1803)

The deal that nearly doubled the size of the United States

When the US bought the territory of Louisiana from France in 1803, acquiring some 828,000 square miles of land, the fledgling nation almost doubled in size overnight.

President Thomas Jefferson had tasked fellow Founding Fathers Robert R Livingston and James Monroe – himself later president – with convincing French leader Napoleon Bonaparte to part peacefully with New Orleans, a major port on the Mississippi River, which was surrounded by that territory.

French control of Louisiana from 1801 threatened access to New Orleans, which had become so crucial to US commerce as it expanded westwards, and the presence of French troops risked the outbreak of hostilities between the two nations.

The rising tension sparked talk of war and secession among the president’s enemies in the opposition Federalist Party. It was, Jefferson related to a French ally, “the embryo of a tornado which will burst on the countries on both sides of the Atlantic”.

But tensions dissipated quickly once Monroe arrived in Paris for negotiations in 1803. Napoleon instructed his ministers to sell the entirety of Louisiana for $15m – equivalent to around $430m today.

Why so easy? The French leader desperately needed money to fund impending wars in Europe. Losing control of Saint-Domingue (now Haiti) to revolution by enslaved people, he was convinced to abandon his hopes in the New World.

At about $18 per square mile, the US acquired that vast swathe of land for much less than its market value. Westward expansion across the continent soon surged as successive missions, most famously the Lewis and Clark Expedition of 1804–06, set out to chart the new territory.

A black and white drawing of a large group of Native Americans sitting around, facing a white man in a hat and cape, having a conversation over a box of goods

Peter Minuit, director-general of the Dutch colony of New Netherland, offers Native American Lenape people trinkets and clothes in 1626, negotiating the sale of what became known as Manhattan Island (Image by Getty Images)

The ‘sale’ of Manhattan Island (1626)

New York’s earliest real estate deal – and its most misunderstood

Today, New York City is notorious for extravagantly expensive property prices. So it’s ironic that, back in 1626, the 23-square-mile island known today as Manhattan was reputedly bought from Native American inhabitants by European settlers for beads and trinkets worth just a few dollars.

After English explorer Henry Hudson, sailing under the flag of the Dutch Republic, came across what’s now called Manhattan Island in 1609, his employers set their sights on owning it.

Manhattan lies on one of the world’s largest natural harbours. With easy access to the Atlantic Ocean and a large population of beavers, it seemed the perfect site for a permanent settlement from which Dutch merchants could cash in on the booming and lucrative North American fur trade.

A few years later, the colony of New Netherland was established on North America’s eastern seaboard. By 1624, Dutch people were living in the lower part of Manhattan Island, establishing a settlement called New Amsterdam.

To deter the British or French from making a claim to the land, in 1626 the colony’s director-general, Peter Minuit, officially purchased it from the Lenape people for a reported 60 guilders (the equivalent of $24).

Despite the popular tale – that the island was sold for a small stash of trinkets – no official deed of the transfer is known to survive. Modern historians think that the Native Americans involved received clothing, weapons and metal tools from the colonists. They may also have assumed that the exchange was only temporary, or that it would allow joint use of the land.

Those Dutch colonists didn’t hold onto Manhattan Island for long. In 1664, English forces captured New Amsterdam in a bloodless takeover, and gave the city a fresh name: New York.

A photograph of a man in a furry black coat and a large black hat

A Métis fur trader – a man of mixed European and Indigenous ancestry – pictured in 1870. Many Métis and First Nations people rebelled when their Red River Colony was sold to the expanding dominion of Canada that year

Sale of Rupert’s Land (1869)

The gigantic Canadian land grab that sparked conflict with Indigenous inhabitants

One of history’s biggest land deals wasn’t between two sovereign nations but between a fur-trading company and the newly confederated country of Canada.

The royal charter granted to the Hudson’s Bay Company by King Charles II of England in 1670 gave it a monopoly over Rupert’s Land, a vast territory spanning 1.5m square miles of North America.

By the 19th century, the HBC was also the de facto administrator of the neighbouring North-Western Territory, which was only a little smaller. And when Canada – initially comprising Ontario, Quebec, Nova Scotia and New Brunswick – determined to expand westward in 1868, these lands stood in the way.

So in 1870, the British government permitted the transfer of Rupert’s Land and the North-Western Territory to Canada at a cost of £300,000 (equivalent to around £45m today).

But in Rupert’s Land, some 12,000 people living in the Red River Colony – most of them First Nations or Métis, of mixed European and Indigenous ancestry – were shocked to learn that, without any warning or consultation, their home was set to become Canadian territory.

Many of them mobilised under the 24-year-old Métis leader Louis Riel, and drove away land surveyors sent by the Canadian government. These rebels then blocked the new lieutenant-governor, William McDougall, at the border, hoping to get assurances that their language, culture and land ownership would be protected. They later declared a provisional government presided over by Riel.

Though the uprising was ultimately quelled, the rebels scored a political victory. Their colony joined Canada as the Province of Manitoba – having shown the authorities just how energetically local people might respond to land transfers.

A large map, with yellow, green and pink colouring, with the words Treaty of Spain in the bottom left corner

A map shows the territory of Florida sold to the US by Spain in 1819. Conflict with native Seminole people in the region continued for nearly four decades. (Image by Albert Bushnell Hart, LL.D., The American Nation Vol. 14 (New York, NY: Harper and Brothers, 1906) - University of South Florida)

The Adams–Onís Treaty (1819)

The deal that brought Florida into the US

Floridians can thank this treaty, named after US secretary of state John Quincy Adams – a man with decidedly expansionist political leanings – and Spanish ambassador Luis de Onís, for their star on the American flag.

With this agreement, inked in Washington, DC in 1819, the US acquired from the Spanish territory spanning some 60,000 square miles in the south-east of the continent. (Florida became a state in 1845.)

In exchange, the US agreed to assume liability for $5 million worth of damage done by American citizens against Spain. It also renounced its claim to Texas, settling the western borders of the US, which had until then been vague and contentious.

The US had already taken control of parts of Florida during a series of military clashes with the Seminole, a Native American people who regularly crossed the border to raid settlements in the neighbouring US state of Georgia.

These US incursions hadn’t been made with the intention of capturing land, only to suppress that Indigenous people, whose willingness to welcome escaped enslaved people also irritated the US. Adams described Spanish Florida as “serving no other earthly purpose than as a post of annoyance” to the US.

The acquisition of Florida, made effective in 1821, was only the beginning of US conflict with the Seminole, however. The heavily outnumbered Native Americans, who employed guerilla tactics, gave up fighting only in 1858.

An engraving showing a group of buildings, with a large flag with a cross on it standing in the middle of the buildings

Fort Christiansborg on the Danish Gold Coast, as it was in 1760. Now called Osu Castle, this bastion was first built in 1661 and used to hold enslaved people, but was sold to Britain in 1850 (Image by Getty Images)

Purchase of the Danish Gold Coast (1850)

When Denmark ceded defunct slave-trading forts to Britain

In March 1850, the UK bought the last forts and settlements in west Africa held by Denmark for £10,000 (equivalent to around £1.2m today).

Denmark had annexed the area from the Swedish in early 1663, and the Danish Gold Coast occupied about 4,000 square miles in what’s now part of Ghana. That coastline came to be dotted with forts, most of them built in the 18th century.

Known as ‘slave forts’, these bastions were commercial hubs used to hold enslaved people before they were loaded onto ships and transported away from Africa.

After Denmark became the first nation in Europe to abolish that brutal trade in 1792 – though in practice, its abolition only came into effect from 1803 – the Gold Coast became increasingly unprofitable. Attempts to establish cotton, sugar and coffee plantations foundered, and all but one of the forts were abandoned in 1817.

So why did Britain, which had abolished slavery in its own empire in 1834, choose to buy the colony and its forts in 1850? Partly, to expand its own influence in west Africa at the expense of France and Belgium, but also to tackle the illegal trade in enslaved people that persisted in the region. Between 1820 and 1870, British Royal Navy patrols seized more than 1,500 slave ships, freeing the 150,000 people held captive on board.

A painting showing three men overlooking a rocky landscape, with horses. The one closest to us is pointing towards the left

Surveyors map Mexican territory in what’s now Arizona and Mexico – land that will be transferred to the US with the Gadsden Purchase of 1853 (Image by Getty Images)

The Gadsden Purchase (1853)

The deal that made a southern US railroad possible

After nearly two years of conflict, in 1848 Mexico was forced to admit defeat and recognise US sovereignty over Texas, which that northern neighbour had annexed a year before the fighting began.

It also ceded huge swathes of territory – totalling 529,000 square miles – across California, New Mexico, Utah and six other present-day states. But if Mexico thought that the US appetite for expansion had been sated, it was sorely mistaken.

The US still didn’t possess the territory it needed to construct a southern transcontinental railroad route – it needed a little more in Arizona and New Mexico. Charged with obtaining land required, former army officer and railroad executive James Gadsden signed a first draft of the Treaty of Mesilla with the Mexican president in December 1853.

Mexico was in financially dire straits and, some historians think, may have feared that refusing to sell up would have prompted the US to invade.

By the next year, the US had acquired about 30,000 square miles of land for $10m (equivalent to around $380m today). Construction of the Southern Pacific Railroad began the following decade, though it was only completed in 1883.

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Piers Mucklejohn is a freelance journalist

Authors

Piers MucklejohnFreelance journalist

Piers is a journalist with a BA in History from the University of Exeter and a master’s degree in Early Modern History from the University of Oxford.

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