Jefferson sent Lewis and Clark to map, trade, and secure the West

Jefferson’s Lewis and Clark expedition joined the centuries-long hunt for Northwest Passage

For centuries, leaders pursued a direct seafaring trade route from Europe to Asia. Jefferson joined this quest by sending Lewis and Clark west, though they confirmed no such practical interior route existed across the continent.

Jefferson omitted a plan to go beyond the Louisiana Territory in his funding request

In January of 1803, the president sought $2,500 to fund the expedition (though it likely cost closer to $50,000). The ostensible rationale for the journey was to explore the newly purchased territory, but Jefferson did not mention he wanted Lewis and Clark to go beyond the newly acquired territory for several reasons.

Explore Lewis and Clark's 8,000-mile journey in Google Earth.

Lewis and Clark’s journey became a blueprint for future exploration

Combining science, diplomacy, and logistics, the Corps of Discovery created a model for later expeditions—from charting the Arctic to NASA’s space missions.

Jefferson feared European control in the West of North America

Jefferson pushed for the Louisiana Purchase to prevent France or Spain from dominating the western frontier, securing control of the Mississippi River and vast lands that he felt were essential to America’s strategic and economic future.

Clark’s maps provided the first detailed record of the American West

Covering over 8,000 miles, William Clark’s maps charted rivers, mountains, and tribal territories with remarkable accuracy. Equipped with sextants, compasses, telescopes, and more, Clark became an expert at surveying—requiring extensive celestial and topographical observations each day.

The Lewis and Clark expedition lasted over two years

The Corps of Discovery departed St. Louis in May 1804 and returned in September 1806, covering more than 8,000 miles by boat, horseback, and on foot. See a timeline of the journey’s key events.

Lewis and Clark encountered more than 70 Native tribes during their journey

The Corps of Discovery’s diplomacy ranged from peaceful trade and vital aid from tribes like the Shoshone and Nez Perce to tense standoffs, most notably with the Teton Sioux, who nearly brought the expedition to a halt.

Meriwether Lewis grew up in the same neighborhood as Jefferson

Hailing from Jefferson’s Albemarle County neighborhood in Virginia, Lewis was a trusted aide and former Army officer. After leading the Corps of Discovery, he became Louisiana Territory governor in 1806, dying three years later under mysterious circumstances.

William Clark negotiated one-tenth of all ratified treaties between Native Americans and the US.

The expedition produced the first detailed climate records of the West

Lewis and Clark logged daily temperature, weather, and seasonal patterns throughout their journey, creating the earliest systematic meteorological record for the western territories of the United States. Their observations helped overturn longstanding views that weather west of the Appalachians was similar to the East Coast.

Madison urged Jefferson to accept the Louisiana Purchase despite constitutional concerns

As secretary of state, James Madison helped negotiate the 1803 Louisiana Purchase and persuaded Thomas Jefferson to proceed, arguing that the strategic and economic stakes outweighed the unresolved constitutional questions.

The Corps of Discovery braved wildlife, weather, and near-starvation

Along their 8,000-mile trek through territory populated by tribes suspicious of their intentions, Lewis and Clark’s party faced many dangers—including grizzly bear attacks, freezing winters, treacherous river crossings, and periods of near-starvation. Watch a 30-minute elaboration of their heroic efforts here.

As president, Thomas Jefferson expanded federal power despite opposing centralized authority

Although Jefferson argued for limited national power, his presidency expanded federal authority through actions such as the Louisiana Purchase, territorial governance, and federal enforcement—reflecting a pragmatic departure from his earlier strict interpretation of the Constitution.

The Lewis and Clark Expedition brought along an estimated 120 gallons of whiskey and still ran out of alcohol halfway through the journey.

The Lewis and Clark expedition purchased more than 260 separate items to supply their journey.

Lewis and Clark identified 122 animal species new to science.

The Lewis and Clark Expedition unexpectedly ran into Sacagawea's long-lost family in the Rocky Mountains.

The expedition documented 240 plant species, 178 new to western science

Lewis and Clark’s botanical records introduced species to Americans like bitterroot, ponderosa pine, and Oregon grape—plants unknown to western science at the time. See a selection of these species in this image gallery.

Discover the 'American Serengeti' Lewis and Clark first recorded

This podcast traces the 19th-century exploration of the Great Plains' biodiversity—beginning with Lewis and Clark's wildlife cataloging and continuing through a century of documenting the Natural West's remarkable species and landscapes.

Native voices share their histories along the Lewis and Clark National Historic Trail

Tribal historians recount their peoples' histories and perspectives on the Lewis and Clark expedition, offering an Indigenous narrative of the lands, encounters, and legacies that shaped the journey.

The Corps traded gifts with many native tribes as a sign of goodwill

They offered peace medals, beads, cloth, and mirrors, while receiving food, horses, furs, and guidance that helped them navigate and survive the western wilderness. This image collection showcases items the expedition collected.

The Louisiana Purchase nearly doubled America’s size in 1803

Acquired from France for $15M, the Louisiana Purchase added 828,000 square miles to the United States—stretching from the Mississippi River to the Rockies. US ambassadors in France signed the papers to buy the tract from the embattled Napoleon Bonaparte for a mere $15M before Jefferson learned the terms, due to the advantageous nature of the deal.

Thomas Jefferson dismissed the Erie Canal as 'little short of madness'

When first proposed, President Jefferson scoffed at the idea of carving a 363-mile waterway through wilderness and rock. With no precedent in American engineering, the canal seemed impossible.

Thomas Jefferson delivered his 1801 State of the Union address in writing

In 1801, President Jefferson ended in-person State of the Union addresses, feeling they were too monarchial, and sent written messages instead—a practice that lasted until 1913. His first message was written and sent via his secretary, Meriwether Lewis, who later led the Lewis and Clark expedition.

The expedition included Clark’s enslaved servant, York

York, Clark’s enslaved servant, played a full role in the expedition—hunting, scouting, and aiding diplomacy with Native nations who were fascinated by his appearance. Despite his contributions, York remained enslaved for some time after the journey, though its uncertain if he remained so for the rest of his life. Explore every member of the Corps of Discovery here.

George Washington was an expert in maps and cartography

Trained as a surveyor, Washington routinely studied, annotated, and drew maps throughout his life. He relied on cartography to navigate frontier lands, plan military campaigns across vast distances, and make strategic decisions on borders, settlement, and governance.

Sacagawea’s skills and presence were vital to the expedition’s success

The group hired French-Canadian trader Toussaint Charbonneau and his wife Sacagawea to serve as translators. Sacagawea became invaluable to the Corps, as she could speak Shoshone and had a familiarity with the geography of the region. Acting as interpreter and cultural bridge, Sacagawea helped secure Shoshone horses, identified key landmarks, and signaled peaceful intent to other tribes.

Madison and Jefferson forged a political alliance that shaped the early US republic

Beginning in the 1780s, James Madison and Thomas Jefferson collaborated closely to oppose centralized power, to found the Democratic-Republican Party, and to guide the nation's early debates on constitutional and foreign policy.

Sacagawea's son, Jean Baptiste, who was born during the Lewis and Clark expedition, traveled to Europe as a duke's companion before returning to the American West.

John Marshall gained national prominence during the XYZ Affair

In 1797, President John Adams sent Marshall to France amid seizures of American ships. French intermediaries demanded loans and bribes before talks, and Marshall refused. Publication of the dispatches fueled the Quasi-War and elevated his reputation in the United States.

Thomas Jefferson and John Marshall clashed over national power and states' rights

Distant cousins Jefferson and Marshall advanced opposing constitutional visions—Jefferson favoring states' rights and local majorities, while Marshall defended broad federal authority and judicial review. Through decisions such as McCulloch v. Maryland, Marshall advanced national supremacy over state resistance.

The 1783 peace treaty with Britain formally ended the Revolutionary War and nearly doubled the size of the United States.

The Barbary Wars were an early test of whether a president could wage war without a formal declaration from Congress

Jefferson sent naval forces against North African pirates without a congressional declaration of war, acting under his own authority. Years later, Madison took the opposite approach and formally sought congressional authorization.

A free archive of firsthand historical documents from explorers of America

Maintained by the Wisconsin Historical Society, the American Journeys collection contains more than 18,000 pages of primary source documents—journals, letters, maps, and accounts written between roughly 1000 CE and the early 1800s. These include eyewitness records of the Norse arrival in North America, Spanish conquistador expeditions, and the Lewis and Clark journey. Browse this list of highlights where pages from the original texts are specified (clicking a link opens a PDF).

At age 22, Washington inadvertently started the French and Indian War.

Lewis brought his loyal Newfoundland dog on the expedition

Meriwether Lewis was accompanied by his dog, Seaman, a Newfoundland who traveled the entire journey—helping hunt, guarding camp, and even rescuing supplies from a river.

A tense standoff with the Teton Sioux nearly ended the expedition

In 1804, the Teton Sioux seized a Corps of Discovery boat during a Missouri River meeting, sparking a dangerous standoff. The conflict eased only after careful diplomacy.

Foreign policy and war defined Madison's presidency

During James Madison's presidency, disputes with Britain and France over trade, maritime rights, and impressment dominated foreign policy, culminating in the War of 1812 and shaping how the United States engaged with major European powers.

John Marshall invested in western land speculation

Like many Virginia elites of his era, Marshall invested in large tracts of western land, including holdings in Kentucky and the Ohio valley. His financial interests mirrored the broader post-Revolutionary pattern of land speculation among political leaders.

The Compromise of 1790 broke a deadlock over debt and the national capital

In 1790, Alexander Hamilton, James Madison, and Thomas Jefferson reached an agreement that allowed Congress to assume the states' war debts and to approve a permanent national capital on the Potomac River.

US westward expansion—and the status of slavery in the new territories—was a major cause of the American Civil War

The addition of new western lands forced the nation to confront whether slavery would spread beyond the South. Each debate over the admission of a new state sharpened the divide between free and slaveholding regions.

Hamilton's endorsement helped win Jefferson the presidency

In the 1800 presidential election, neither candidate won a majority in the Electoral College, sending the decision to the House of Representatives. After 36 failed votes, Alexander Hamilton lobbied for his ideological rival, Thomas Jefferson, over Aaron Burr, helping break the deadlock.

Marshall was briefly secretary of state and chief justice at the same time

Appointed secretary of state by John Adams in 1800, Marshall oversaw foreign policy during disputes with France, Britain, and Spain, including support for the Convention of 1800. For about a month in early 1801, he served as both secretary of state and chief justice.

James Monroe first outlined what became known as the 'Monroe Doctrine' during his 1823 Annual Message to Congress

President Monroe used his Annual Message to Congress to warn European powers against further colonization in the Western Hemisphere, asserting US opposition to foreign intervention and laying the foundation for a cornerstone of American foreign policy that remains to this day.

The US finished what the French had started with Panama's canal

For about two decades, Suez Canal-builder and Frenchman Ferdinand de Lesseps led the project, but financial troubles forced it into the hands of the US, who completed it in 1914. This timeline, made to accompany the definitive PBS American Experience documentary about the canal, highlights major moments in its construction.

See how the Declaration evolved from draft to final text

John Adams urged Congress to choose Thomas Jefferson to draft the Declaration because of his literary skill and low-profile reputation. Read Jefferson's initial draft, which included passages later removed, including a forceful denunciation of slavery.

The Erie Canal fueled a surge in westward settlement

By providing cheap, reliable transport to the interior, the canal made western lands more accessible. Farmers, traders, and immigrants moved into the Great Lakes region, accelerating population growth.

See Pierre L'Enfant's original plan and vision for DC and the National Mall

Americans touring the Louvre were inspired to create their own grand museums

The one-time royal residence was first transformed into a public museum in 1793 amid the French Revolution. Americans visiting in the early 1800s were both turned off by the aristocratic grandeur and compelled by the open access to the public. James Fenimore Cooper, the author of "The Last of the Mohicans," apparently came and measured the length of galleries.