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8.4-8.5.10 A Map of Lewis and Clark's Track, across the western portion of North America from the Mississippi to the Pacific Ocean: by order of the executive of the United States in 1804, 5 & 6

History of the expedition under the command of Captains Lewis and Clark, 1814.
Lewis, Samuel, Clark, William, Harrison, Samuel, Bradford and Inskeep.
Library of Congress

Lewis, Samuel, 1753 Or, William Clark, Samuel Harrison, and Bradford and Inskeep. A map of Lewis and Clark's track, across the western portion of North America from the Mississippi to the Pacific Ocean: by order of the executive of the United States in , 5 & 6. [Philadelphia: Bradford and Inskeep, 1814] Map.

This map of the American West — drawn by William Clark, co-leader of the Lewis & Clark expedition — was published in 1814 with the first complete set of the Lewis and Clark journals. Note the much greater level of detail compared to Source 9, the earlier map. William Clark was the expedition’s primary cartographer (map maker). Although nine of the thirty-plus expedition members who traveled west from North Dakota to the Pacific coast kept journals, only Clark made noteworthy maps. Clark used the geographical observations made by the expedition’s members (such as latitude measurements taken from the angle of the sun or stars, the layout of rivers and mountains, and the like). But he also relied upon the geographical knowledge of Native Americans they met. Remember that the West much beyond the Mississippi River — and outside of well-traveled corridors like the Missouri River — was little known to Euro-Americans before 1804. 


Compare this map to Source 9, the 1804 map of the West published before Lewis and Clark’s journey. What differences do you notice between the two, both in level of detail, and how the West is depicted—from the Mississippi River to the Rocky Mountains, and from the Rockies to the Pacific Ocean?

What other major rivers and geographical features can you find on the map? Which Native American tribes did Clark label?

How do you think this map might have informed future travelers, such as US government explorers or trappers / fur traders who traversed the trans-Mississippi West in the coming decades?


The Lewis & Clark Expedition created some 140 maps. Clark was the only notable cartographer among the Corps of Discovery. This map is probably a compilation of detailed maps he worked on during the long winter stays at Fort Mandan, North Dakota (1804 – 1805), and Fort Clatsop near the Oregon coast (1805 – 1806). Lewis and Clark relied on many sources to piece together their maps: direct observation, plus maps compiled from Native Americans and Euro-American fur trappers and traders. 


As noted in the material that accompanies Source 3, a key goal of the Corps of Discovery was mapping and securing the US claim to the Louisiana Territory. Jefferson also wanted Lewis and Clark to establish a US claim to the “Oregon Country”: all the territory west of the Rocky Mountains to the Pacific Ocean, which included present-day Oregon, Washington, and parts of Idaho and Montana. (The Louisiana Purchase ended at the crest of the Rockies.) Maps such as those produced by Lewis and Clark were, in the long term, tools of conquest as Euro-Americans entered onto Native American territory; they were not neutral or benign undertakings. Maps such as Clark’s, pictured here, had a presumed agenda: not only to “stake a claim” to Indian lands but also to keep out other European powers, such as the British to the north.


This map was the first detailed Euro-American description of the Rockies, and the tributaries of the Missouri and Columbia rivers, the major rivers that Lewis and Clark traversed. Students will see tributaries of these major rivers labeled, such as “Lewis’s River” (the Snake River) — which the explorers followed in present-day Idaho and Washington to reach the Columbia. Students might also observe how extensive the Rocky Mountains are: multiple, twisted chains of mountain ranges, some 100 miles wide where Lewis and Clark crossed from Montana into Idaho. They can compare many features on this map with the Source 9 map. Native Americans, of course, produced their own types of maps — including petroglyphs depicting river systems, relief maps made on the ground by heaping dirt to show rivers and other features, and verbal descriptions of a certain territory (many of which Clark wrote down or sketched firsthand). Source 11 is a Native American–produced map of the Missouri River, and students will be able to make comparisons between that and Clark’s 1814 map.


The American claim to Oregon was caught up in US–British relations. Both nations jointly claimed the Oregon Country until 1846, when a treaty granted to the United States the region west of the Rockies and south of 49° north latitude. US mapping efforts plus Lewis and Clark’s 1805 – 1806 visit — traveling down the Columbia River and spending the winter near the Oregon coast — were as important to the US claim as the treaty itself. In 1793, British explorer Alexander Mackenzie became the first European to traverse the North American continent north of Mexico when he reached the Pacific coast of British Columbia, giving Britain an early claim to the Northwest. However, Lewis and Clark were the first Euro-Americans to set foot in the present-day US Pacific Northwest. Starting in the 1830s and ’40s, white American overland migration to the West — on the Oregon Trail and other routes — followed, bringing with it much upheaval and violence for Native peoples.


This is a hand-drawn, black-and-white map published in 1814, entitled “A Map of Lewis and Clark’s Track, Across the Western Portion of North America, from the Mississippi to the Pacific Ocean, by Order of the Executive of the United States, in 1804, 5, & 6.” It depicts the western portion of North America, from the Great Lakes (only Lake Superior is shown) and the Mississippi River west to the Pacific Ocean. The map covers territory as far north as the Strait of Juan de Fuca (the entrance to Puget Sound, west of present-day Seattle), and as far south as present-day Colorado and Utah. The most detail is provided for the Rocky Mountains - which are depicted as many complex chains of mountain ranges - and the Missouri and Columbia Rivers and their tributaries. It also labels the locations and estimated populations of Native American tribes whom Lewis and Clark encountered on their two-year journey, such as the Chinook, Shoshones, Blackfeet, Assiniboines, Mandan, and Teton Sioux.