Michael Blanding is the author of The Map Thief: The Gripping Story of an Esteemed Rare-Map Dealer Who Made Millions Stealing Priceless Maps.

America was made out of pieces of paper. There are the pieces we all know about—the Declaration of Independence, the Constitution, the Bill of Rights. Then there are those lesser-known sheets of paper on which the changing features and borders of our country were drawn.

Maps have played a crucial role, ever since the discovery of the New World, in publicizing the discoveries of explorers, altering perceptions of control, and refereeing the claims of competing powers in finally setting the shape of the United States of America. It’s not too strong a statement to say that without these pieces of paper, the United States as we know it would never have existed—or else, it would look radically different today. Here are 10 of the most important maps in making the dream of our nation a reality.

1. Henricus Martellus // “Untitled [Map of the world of Christopher Columbus].” Manuscript Map, 1489.

Courtesy of the Beinecke Rare Books and Manuscript Library, Yale University

When Christopher Columbus set sail for the New World in 1492, he did it with a map in hand—this one, or one very much like it. Only two copies survive of this map, drawn by German cartographer Heinrich Hammer, who Latinized his name in the fashion of the day to Henricus Martellus Germanus. They have the distinction of being the most complete picture of the world as Columbus and his contemporaries saw it. In fact, Columbus may never have set sail at all if it weren’t for the story that the map told, a story that ultimately would be proven false.

Some background: No educated person in Columbus’ day really thought the earth was flat—the Greeks had determined it was round more than a millennium before. And some Greek astronomers and mathematicians had even accurately calculated the earth’s circumference at 25,000 miles. But Martellus relied on the wrong mathematicians, who calculated the circumference at only 18,000 miles. He also dramatically extended the length of Asia to 7000 miles longer than it actually is—making it seem like a quick trip sailing west across the ocean from Europe to Japan. That gave Columbus the confidence to argue to Spain’s Ferdinand and Isabella that a western route to the Spice Islands was not only doable, but would also be easier than sailing around Africa. Of course, as we now know, that wasn’t the case, as Columbus found when he ran smack into another continent in the way. So confident was Columbus in his map that he died believing he’d found Asia—when really he’d found a new continent entirely.

2. Martin Waldseemüller // “Universalis Cosmographia Secundum Ptholomaei Traditionem et Americi Vespucii Alioru[m]que Lustrationes.” St. Die, 1507.

Courtesy of Library of Congress, g3200 ct000725C.

The most expensive map ever purchased, this map was sold to the Library of Congress in 1989—for a cool $10 million. Why the fuss? The entire value can be traced to one word that appears on this map for the first time in history: America. Even though Columbus got there first, Christopher never claimed to have discovered a new continent. By contrast, a self-promoting Italian sailor named Amerigo Vespucci loudly declared to anyone who would listen that he had discovered a new continent on his voyages west from Portugal—and in a pamphlet, he described the native inhabitants in intimate detail. “Everyone of both sexes goes about naked,” he wrote, continuing that “the women… although they go naked and are exceedingly lustful, still have rather shapely and clean bodies.”

Such titillating prose ensured a wide distribution for his pamphlets, which eventually fell into the hands of a young German mapmaker, Martin Waldseemüller. He, in turn, was putting together a new atlas of the world that included a sliver of land in the west that was beginning to show up on Portuguese charts. For the first time, Waldseemüller surrounded that sliver completely by water, and reasoning that all of the other continents were named after women, he feminized Amerigo’s first name to create the name “America” to describe it.

Unfortunately, doubts started appearing almost immediately about whether Vespucci had even been on a voyage, much less whether he’d discovered a new continent, and in later editions of his map, Waldseemüller took the name off of the new land, calling it merely “Terra Incognita” instead. But the name had already stuck, giving us the name of our continent, and our country, today.

3. Captain John Smith // “New England.” London, 1616.

Courtesy of Beinecke Rare Book & Manuscript Library, Yale University.

We all know John Smith from his role in founding the Virginia Colony—and for his role along with Pocahontas as one half of America’s original “power couple.” But after he was drummed out of Virginia for reasons best not gone into here, Smith had a second act exploring the area then known as “North Virginia.” Smith figured it needed a catchier moniker, so he branded it “New England,” both to separate it from the southern colony that spurned him and to tell other European countries “hands off.”

Of course, John Smith also wanted to claim it for John Smith, and so he included a giant portrait of himself taking up a corner of the map, which he used to illustrate a book about the new lands he’d discovered. (In later editions of the map, he even updated the portrait, making his beard fuller and bushier.) More brazenly, in order to claim the territory for England, he offered the map to the crown prince Charles and asked him to change the names of all of the native villages to names of English towns—creating a fictional geography that might entice colonists to found such towns for real. Most of those names have since fallen by the wayside—but one has survived. When the Pilgrims sailed from Plymouth in 1620, they did so with a copy of Smith’s map in hand, steering their way to an attractive harbor that Smith had coincidentally named “Plimouth.” Upon arrival, they took the name for their own, and there it remains on the map to this day.

4. Guillaume De L’Isle // “Carte De La Louisiane et du Cours du Mississipi.” Paris, 1718.

Courtesy of Library of Congress, g3700 ct000270.

The English may have claimed New England, but the rest of the continent was still very much up for grabs throughout the 17th and early 18th centuries—and the French decided they wanted a piece of it. In fact, as this map shows, they wanted a big piece of it.

An early example of cartographic propaganda, this map plays fast and loose with borders to claim virtually all of North America for the French, splashing “La Louisiane” in big letters across the continent’s midsection, and squeezing the English colonies almost entirely off the page. It even claims “Caroline” was named for the French king Charles IX, not the English kings Charles I and Charles II.

This was no idle threat—at the time, Guillaume de l’Isle was arguably the greatest mapmaker of his age, employing new scientific methods to more exactly survey the land, and his map was much more accurate than any English maps at the time. When the English saw it, they were incensed, no doubt fuming about French audacity, and British mapmakers began producing maps of their own that exaggerated English claims in North America at the expense of their enemies across the channel. That spurred the French to produce more propaganda maps in response, and for 35 years, the two countries duked it out in a paper war over who owned the continent.

Eventually, the paper war broke out into a real war, which we know as the French and Indian War, to decide who owned the continent in reality. England emerged victorious, taking all of the territory south of the Great Lakes and east of the Mississippi, and pushing Louisiana off the map to the west of the river.

5. John Mitchell // “A Map of the British and French Dominions in North America.” London, 1755.

Courtesy of Library of Congress, g3300 ar003900.

Produced as part of the one-upmanship between England and France in their “paper war” over control of North America, this map by Virginia native John Mitchell boldly claims nearly all the continent for England. South of the Great Lakes, in fact, Mitchell lets loose, extending the borders of Georgia and the Carolinas west straight across the Mississippi, presumably to the Pacific. (Imagine today if North Carolina was 3000 miles long!)

But none of this is what caused a former head map curator at the Library of Congress to declare Mitchell’s map the “most important map in American history.” The reason for that is its role not in starting a war, but in ending one. When British and American diplomats met at the end of the Revolutionary War to draw the definitive boundary between the United States and Canada during the 1783 Treaty of Paris, they relied upon Mitchell’s map to set the borders of the new nation, creating for the first time the concept of an independent United States of America. Unfortunately, the language in the treaty setting the boundary was ambiguous, especially in the west. That has sent American and Canadian officials back to the map countless times during the last 200 years in order to argue over the exact course of the border, which was not definitively set in some spots until 1984. (And, in fact, some islands in the Gulf of Maine are still in dispute.)

Fun postscript: During treaty negotiations, a British diplomat drew a red line across the map up to the point he thought the Americans would claim—when the Americans claimed less, however, he hid the map, and the so-called “red line” map remained hidden in the British archives for decades, lest the Yanks catch wind of the fact that they could have gotten more of the continent than they did.

6. Aaron Arrowsmith // “A Map of the United States of North America Drawn from a Number of Critical Researches.” London, 1802.

Courtesy of The New York Public Library. www.nypl.org.

When the United States had been formed in 1783, the most accurate large-scale maps of North America were decades old and full of errors and misconceptions. Ironically, it was an English cartographer named Aaron Arrowsmith who diligently gathered information in order to create the first comprehensive map of the new country. He drew from a variety of sources, including reports by Native Americans which had been brought to him by Hudson Bay fur traders. In his synthesis of the resulting data, he proved particularly adept at weighing the relative merits of different cartographic sources and selecting the ones that proved most accurate. His resulting map, first produced in 1796, was not only then the most accurate map of the existing United States, but also faithfully sketched the unexplored territory west of the Mississippi that the new country was soon to acquire.

Arrowsmith constantly updated his map for years after the original release, and the 1802 edition shows the borders of the U.S. just before President Thomas Jefferson completed the Louisiana Purchase. Thus, the map was the one that Meriwether Lewis and William Clark used to plot their famous expedition across the continent, choosing the Missouri River for their route since it appeared to be the fastest way west.

7. William Clark // “A Map of Part of the Continent of North America.” Manuscript map, 1810.

Courtesy of the Beinecke Rare Book & Manuscript Library, Yale University.

With the Louisiana Purchase of 1803, the United States more than doubled its land area. The only trouble was, most of the new territory was a vast no-man’s land that had been little traveled—and mapped even less. President Thomas Jefferson’s mandate to explorers Meriwether Lewis and William Clark was clear: find “the most direct & practicable water communication across the continent.”

Setting out on their mission, Lewis and Clark headed west up the Missouri River, hoping to find a short portage to another river flowing the opposite direction down to the Pacific Ocean. What they found, instead, was a vast, seemingly impenetrable mountain range with peak after peak to traverse before they could hope to reach the Pacific. A trained cartographer, Clark took meticulous surveys of the Rockies during the 1804–1806 expedition, and later updated his maps with new information from other explorers such as Zebulon Pike. The manuscript map he produced in 1810—which was eventually printed by Samuel Lewis (no relation to Meriwether) in 1814—forever ended American hopes of finding a water route across the continent; at the same time, it brought back the first picture of new resource-rich lands that would eventually be even more important to the fate of the nation.

8. John Melish // “Map of the United States with the Contiguous British and Spanish Possessions.” Philadelphia, 1816.

Courtesy of Library of Congress, g3700 ct000675.

At the start of the 19th century, most maps were still printed in well-established firms in London, Paris, and Amsterdam by cartographers who had their knowledge passed down through generations of masters and apprentices. One of those mapmakers, a Scot named John Melish, traveled extensively in the new United States in the early 1800s—but instead of going back home to make his maps, he set up shop in Philadelphia as the first true American mapmaker. And he entered the field with a bang with this indisputable masterpiece, published in 1816, which shows for the first time something approximating the outline of the United States we know today. In fact, as Melish later recounted, he was originally planning to draw the boundary of the country at the Continental Divide in the midst of the Rockies—but decided instead to claim U.S. territory as far as the Pacific since “part of this territory unquestionably belongs to the United States.”

Actually, there was a very big question about to whom the wild, unexplored Northwest belonged—to say nothing of the disputed lands of Texas, which Melish also boldly claimed from the Spanish. Melish’s map, continually reprinted and updated over the years, began to put those questions to rest, however, cementing in the minds of people all over the world that the U.S. was truly a transcontinental proposition. Many historians see in the map the visual representation of the idea of “Manifest Destiny”—the claim that Americans had the somehow inalienable right to settle the full length of the North American continent. One adherent of that claim, Thomas Jefferson, proudly put a copy of Melish’s map in the entrance hall of his estate, Monticello, and future presidents used it in treaty negotiations with European powers to push the boundaries of their ever-growing country.

9. John Disturnell // “Mapa de los Estados Unidos de Mejico.” New York, 1847.

Courtesy of Library of Congress, g4410 ct000127.

Although Texas was formally admitted to the Union in 1845, the country of Mexico didn’t quite agree with the southern boundary claimed by the state at the Rio Grande. A year later, they attacked across the river, and the United States declared war.

As battles raged across the Southwest, many Americans followed along on this map produced by New York guidebook publisher John Disturnell, who had conveniently released it around the same time. Unfortunately, Disturnell was not himself a cartographer, and his map was wildly inaccurate in places, placing El Paso, for example, some 34 miles north and 100 miles east of its true location. One contemporary explorer called the map “one of the most inaccurate of all those I have seen.”

Despite those faults, however, when the war ended in 1848 and the United States gained not only Texas but also California, Nevada, Utah, and much of New Mexico and Arizona, diplomats appended Disturnell’s faulty map to the Treaty of Guadelupe Hidalgo in order to set the boundary lines between the countries. That meant no end of headaches for future generations of surveyors called in to reconcile the map with the treaty language in order to determine the true southern boundary of the United States—which, in some cases, wasn’t finally fixed until 1963. On the plus side, the inaccuracies in the map led to a flurry of government surveying in the West that produced many more accurate maps of the territory sooner than might have otherwise been done.

10. U.K. Met Office // “Allied Forces Chart for 6 June, 1944 at 1300.” London, 1944.

Courtesy of U.K. Met Office.

Most of the most important maps in United States history date from the 18th and 19th centuries, when the country was young and the boundaries were being set. One map from the 20th century that played a crucially important role in determining the balance of U.S. history, however, wasn’t a map of America at all, but a map of the English Channel produced by the U.K. Met Office.

The British government office responsible for weather forecasts made the map on June 6, 1944, the day of the largest military invasion in history: when the Allied Forces in World War II landed in Normandy during D-Day. In fact, the invasion was originally scheduled to be launched on June 5, 1944—but a Scottish weather forecaster, Captain James Stagg, warned against it due to clouds and strong winds that would have hindered air cover for the invasion. U.S. General Dwight Eisenhower waited with bated breath for the word the following day; if the weather didn’t clear, then the Allies would have to wait another two weeks until the tides and moonlight were right.

After consulting all of the information he had—including German meterological data acquired by Allied code breakers—Stagg produced this map, which showed an afternoon break in the weather. Eisenhower gave the word “go,” and the invasion went off as planned, allowing the Allies to begin their inexorable drive to Berlin. Had they gone a day earlier, the invasion might have failed, and it might have taken another year for the Allies to defeat Germany, possibly giving the USSR much more of Europe after the war. Later, it was discovered that the Germans had actually botched their own forecast that day, earning the Allies the element of surprise. As for Stagg, he sent another map to Eisenhower two weeks later showing that, had the Allies waited, they would have run into the worst storms in the English Channel in decades. “Thanks,” wrote Ike on the map, “and thank the Gods of war we went when we did.”

Michael Blanding is a Boston-based investigative journalist. The Map Thief: The Gripping Story of an Esteemed Rare-Map Dealer Who Made Millions Stealing Priceless Maps, was published by Gotham Books and named a New England Indie Bestseller by the New England Independent Booksellers Association. This post originally appeared in 2014.