Meriwether Lewis Gets His Marching Orders

Over the next several months Smithsonian plans to run excerpts from the journals of the members of the Corps of Discovery, better known as the Lewis and Clark expedition, and other documents. We begin this month with Jefferson’s June 20, 1803, directive to Meriwether Lewis outlining the president’s goals for the expedition. We’ve kept his sometimes unique spelling and punctuation; brackets indicate words or phrases that Jefferson, for whatever reason, deleted on the manuscript.

To Captain Meriwether Lewis esq.
Capt. of the 1st regimt. of Infantry of the U.S. of A.

The object of your mission is to explore the Missouri river, & such principal stream of it, as, by it’s course and communication with the waters of the Pacific ocean, whether the Columbia, Oregan, Colorado or any other river may offer the most direct & practicable water communication across this continent for the purposes of commerce.

Beginning at the mouth of the Missouri, you will take [careful] observations of latitude & longitude, at all remarkeable points on the river, & especially at the mouths of rivers, at rapids, at islands, & other places & objects distinguished by such natural marks & characters of a durable kind, as that they may with certainty be recognised hereafter....

The interesting points of the portage between the heads of the Missouri, & of the water offering the best communication with the Pacific ocean, should also be fixed by observation, & the course of that water to the ocean, in the same manner as that of the Missouri.

Your observations are to be taken with great pains & accuracy, to be entered distinctly & intelligibly for others as well as yourself.... Several copies of these as well as of your other notes should be made at leisure times, & put into the care of the most trust-worthy of your attendants, to guard, by multiplying them, against the accidental losses to which they will be exposed....

As far up the Missouri as the white settlements extend, an intercourse will probably be found to exist between them & the Spanish posts of St. Louis opposite Cahokia, or Ste. Genevieve opposite Kaskaskia. From still further up the river, the traders may furnish a conveyance for letters. Beyond that, you may perhaps be able to engage Indians to bring letters for the government to Cahokia or Kaskaskia, on promising that they shall there receive such special compensation as you shall have stipulated with them. Avail yourself of these means to communicate to us, at seasonable intervals, a copy of your journal, notes & observations, of every kind, putting into cypher whatever might do injury if betrayed....

Given under my hand at the city of Washington this 20th day of June 1803.

TH: J. Pr. U.S. of A.