During their 1803--1806 expedition, Lewis and Clark mapped the lands, described the natural wonders, and encountered the people of western North America.

President Thomas Jefferson gave the Corps of Discovery explicit instructions to keep field notes and diaries on the trip. These journals were a treasure-trove of information on geography, geology, flora and fauna, and local inhabitants.

Geography

The journals of Lewis and Clark contain a wealth of geographical information about the areas they passed through. President Thomas Jefferson had instructed them to keep meticulous records of their observations, and the result is a national treasure.

Geography is a field of study that focuses on questions like where things are and how they are related to each other. It also includes the study of human culture, spatial relationships, and interactions between humans and the environment.

A basic idea of geography is that everything is related to something else. This is called the first law of geography.

Areas that receive heavy rainfall all year round are classified as rainy tropical lands. They include areas such as the Amazon basin and Congo basin.

People living in these regions produce food, clothing, tools, and shelter. They do many different kinds of work for a living, such as mining, grazing, farming, lumbering, manufacturing, and fishing.

Natural History

When President Thomas Jefferson dispatched Captains Meriwether Lewis and William Clark on their great exploration of the West, he commanded them to keep meticulous records on the geography, ethnology, and natural history of the region. In their leather-bound notebook journals Lewis and Clark compiled hundreds of pages of observations.

In the course of their exploration Lewis and Clark identified or carefully described for the first time 178 plants and 122 animals. Many of these creatures, including pronghorn, grizzly bear, swift fox, and black-tailed prairie dog, were new to science.

The natural history of the expedition was underappreciated for over a century and is now recognized as one of the great contributions to American scientific knowledge. For this reason, many scientists today find the journals of Lewis and Clark fascinating.

As a result, archivists have struggled to reconcile the clean and polished nature of Lewis and Clark?s journals with the fact that they were written on one of the most difficult expeditions ever undertaken in the United States. Despite these difficulties, the journals continue to be admired and studied by many historians.

People Encounters

The people encountered on Lewis and Clark's journey formed a significant part of their journals. Some Indians were friendly and open to trade, while others were wary of white men and their intentions.

Some Indians, like the Brule Teton Sioux, were more hostile and resisted settlers' efforts to settle on their land. Some, such as the Otoe and Odo, were hospitable and willing to conduct peaceful Indian councils with the Corps of Discovery.

While at Fort Mandan, Lewis and Clark hired French-Canadian trapper Toussaint Charbonneau as an interpreter, who was joined by his pregnant Shoshone wife, Sacagawea. She became an important and respected member of the expedition party and helped to communicate with many Indians along the way.

Navigation

During the two-year expedition to explore the new lands of western North America, Lewis and Clark used several navigational aids and devices. These included a sextant, an octant, a chronometer and several types of artificial horizons (see photo below).

The celestial observations the captains made at camp were crucial to their route survey and to the accuracy of their map-making. Specifically, they needed to determine the difference between magnetic north and true north, called magnetic declination.

In addition to these instruments, the expedition carried a circumferentor, or surveying compass. The surveying compass could be used to make the course of the expedition between two reference points and was thus the most important navigational instrument on the trip.

Throughout the trip, Lewis and Clark recorded their daily observations of local features in their journals. They also made detailed astronomical observations when atmospheric conditions permitted, usually at camp during the night.