I’m delighted to tell you that a review of our new Levenger Press book Mapping the West with Lewis and Clark in the Winter 2015 edition of the professional journal Portolan described it as “accessible to a wide audience, ranging from the generally educated reader to those with more specialized interests in the Corps of Discovery and its landmark expedition. Although thousands of books and papers have been written about the expedition, this one fills a unique niche.”
I’m proud of the modest contribution we’ve been able to make to bring you some of America’s history as it really was. I hope you’ll have a chance to read for yourself why this book matters. In the meantime, enjoy this conversation with author Ralph Ehrenberg of the Library of Congress.
— Steve
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It was the stuff of Undaunted Courage, the Lewis and Clark expedition of 1804-06 into the American West. President Thomas Jefferson was the impetus behind it, and even he had certain assumptions about what the rest of the country looked like. Surely any mountains to the west would be no higher than those on the East Coast…
But Jefferson was happy to be proved wrong, and he trusted the expedition’s captains—Meriwether Lewis and William Clark—to paint a picture of the American West, not with a brush but with compasses, octants and sextants.
In Mapping the West with Lewis and Clark, two experts on the Lewis and Clark track show us how Lewis and Clark changed our history through the maps that they produced. Clark's final 1814 map was far from perfect (for starters, Pike’s Peak was higher and not quite where he placed it), but it was thanks to this map that Americans could for the first time grasp the scale of the country they lived in.
Ralph Ehrenberg, the chief of the Geography and Map Division at the Library of Congress, got hooked on the maps of Lewis and Clark when he was working on a biography of the first surveyor of the city of Washington, who had prepared some of the expedition’s major planning maps.
Then his colleague at the Smithsonian, Herman Viola, a curator emeritus and leading expert on American Indians in the West, convinced Ralph to join him as a study leader on his annual Lewis and Clark Horseback Trip over the Lolo Trail in Idaho. This despite the fact that Herman is deathly allergic to horses. (“How many days are you on horseback?” his allergist asked him. Four. “I can keep you alive for a week.” Which he did—every week for the 16 years Herman led the trek.) In his work, Herman has met descendants of the Nez Perce Indians who befriended Lewis and Clark.
As so often in history, there’s a story behind what we know, what we think we know, and what we’ve heard about the Lewis and Clark expedition. Here are excerpts from one of many conversations that Levenger Press founding editor Mim Harrison had with Ralph:

Levenger Press: We tend to think that Lewis and Clark were going into a completely unknown wilderness when they set off from St. Louis. Were they?
Ralph Ehrenberg: The Far West was unknown when Jefferson and Lewis first discussed the expedition, and no maps accompanied the Louisiana Purchase Treaty. But Spanish, British, and French trappers and traders had reached the Mandan Villages on the Missouri River near present-day Bismarck, North Dakota, by the 1790s. Additionally, there were maps sketched on the ground by Blackfeet hunters for Hudson’s Bay Company surveyors that provided information about rivers, routes, and Indian villages for large swaths of the Far West.
LP: Jefferson wrote a rather cagey letter to Congress in early 1803 where he asked for $2500 to “send a few soldiers up the Missouri River,” as you wrote, to see about trading with the western Indian tribes. What was his real agenda for the Lewis and Clark expedition?
Ralph: In addition to locating a possible Northwest Passage that could link the west and east coasts of North America, he wished to learn more about the region’s vegetation, weather conditions, and wildlife—especially animals believed to be rare or thought to be extinct.
LP: What about trading with the western tribes?
Ralph: Jefferson wanted to know the strength, militancy, and life ways of American Indians. Above all, he wanted to map the interior of the continent so others could follow in Lewis and Clark’s path. 
LP: The American Indians played a critical role in mapping the American West. How was their view of a map different from European Americans’?
Ralph: Indian maps were designed to supplement or remind their intended users of what they already knew or may have forgotten. Networks of rivers and trails served as the basis for the structural framework rather than latitude and longitude, and they did not distinguish between the two. Distance and scale were based on the time required to travel between campsites or landscape features.
LP: How did Lewis and Clark capture the Indians’ information, since it wasn’t written on paper?
Ralph: Indian mapmakers recorded and transmitted concepts of their landscapes—cultural, physical, and sacred—using a variety of transitory cartographic devices. These included inscribed maps sketched with charcoal on animal skins, or scratched in the ground or snow; raised-relief maps modeled with sand, dirt, or snow; and “mental maps” illustrated through hand signals or sign language, the universal means of communicating among American Indians.
LP: What was involved in Lewis or Clark asking an American Indian a question, given that the two would not have spoken the same language?
Ralph: Exchanges between them often involved dialogue with several intermediaries. Such “translation chains” would normally include one of the expedition’s French-speaking voyageurs as well as one or more Indians from different tribes. One of the expedition members, George Drouillard, was of French-Canadian and Shawnee heritage. He was a proficient sign-talker and also spoke seven Indian languages.
LP: How long might it take to get a reply that everyone was happy with?
Ralph: In one instance Lewis and Clark posed a question about a map that had to be translated eight times through four languages—French, Minitari (modern Hidatsa), Shoshone and Nez Perce. The exchange required five to six hours.

LP: What were the steps involved for Lewis and Clark in creating a map?
Ralph: Clark was the mapmaker, and he created two types of maps—field maps and regional maps. Field maps were plotted from daily measurements for directions and distances that were taken during each change of the course of travel along the expedition route. Clark compiled the regional maps from the field notes during their winter camps at Fort Mandan and Fort Clatsop. He also added information from Indian maps and from Indian hunting and war parties.
LP: What instruments did they use?
Ralph: Directions were determined by compass readings, using either a plain surveyor’s compass or a brass boat compass. Distances between compass bearings were determined by the log-line (a wooden float) on water, and on land by estimates, or pacing. These daily “courses and distances” were written in the field notes or on scraps of paper, and then plotted at the end of the day on grid paper at various scales, using a small compass that Clark attached to his gold watch chain. Lewis then used celestial observations to correct the compass errors that accumulated. Lewis and Clark also carried a chronometer to determine longitude. It was the first high-precision clock to be carried on a long inland expedition, but it proved unreliable.
LP: What were some of the more colorful notations that Clark made on the hand-drawn maps?
Ralph: One of the most interesting is “The place called by the Indians Hill of little Devils,” which appears on Clark’s route map of August 21-26, 1804. It’s a reference to the “Little People” or “Little Spirits,” leprechaun-like healers and pranksters believed by the Indians to live in the hills and mountains of many Northern Plains’ tribes. This notation was transformed to “Spirit Lake” on Lewis and Clark’s 1814 map. On the opposite side of “Little Devils,” Clark’s 1805 Fort Mandan regional map includes a reference to “Big Devils,” a name he associated with a band of Assiniboine. This linkage may be a corruption of the band’s original name. More likely, it reflected the antipathy that Lewis and Clark developed toward the Assiniboine because of their trade association with the British and their nomadic, war-like nature.
LP: Have the names been preserved on modern maps?
Ralph: Yes. You’ll see “Spirit Lake” listed in South Dakota and “Devils Lake” in North Dakota.
LP: Can you describe the American Meridian that Jefferson wanted for Lewis and Clark’s maps?
Ralph: The American Meridian was to be America’s Greenwich meridian, the imaginary north-south line from which mapmakers and astronomers indicate zero-degree longitude. Jefferson saw it as a symbol of U. S. independence from Britain and believed it should serve as the base line for all of Lewis and Clark’s maps. Two American meridian lines were surveyed, one through the President’s House—now the White House—and one through the Capitol Building. It is unclear which was used for Lewis and Clark’s 1814 map.
LP: Does anyone today use it?
Ralph: American map publishers used the American meridian into the early nineteenth century. In 1884 the International Meridian Conference, held in Washington, D. C., established the Greenwich, England, meridian as the international standard for zero-degree longitude.

LP: Would it be fair to call Lewis and Clark expert synthesizers of data, in that there were maps made in Europe of North America that they used in their planning phase, and maps that European traders in America used as well?
Ralph: I would say that one of their great strengths is that they were good at using data that others had synthesized. They were adept at comparing and adjusting such data with first-hand field observations and what they obtained from Indian sources. During the expedition, they constantly adjusted their preconceived notions and did not hesitate to add Indian information when it was appropriate.