It’s tempting to picture the Lewis and Clark expedition as a journey into a blank space on a map. It wasn’t. The land was already known and traveled by Indigenous peoples, whose geographic knowledge was crucial to the expedition. What was incomplete was the map available to US expedition planners.
Before the expedition
That distinction makes pre-expedition maps fascinating. An annotated 1803 Lewis and Clark map shows the kind of geographic picture explorers could begin with. Rivers, lakes, and routes could be recorded, but major questions remained about how the waterways and lands to the west connected.
After the journey
Now compare that starting point with A Map of the Discoveries of Capt. Lewis & Clark (1807). Rather than treating either map as the final word, read them as snapshots of knowledge at different moments. Look for changes in the courses of rivers, the placement of landmarks, and the areas given more detail. Where does the later map seem more certain? Where might it still be interpreting reports rather than presenting a complete survey?
This is the best reason to display the two maps together. They don’t just trace a route; they show how geographic information was gathered, shared, and turned into a printed account. They also open the door to a fuller conversation about whose knowledge informed those maps and whose names and perspectives printed maps often left out.
