Thomas Jefferson tasked Meriwether Lewis with exploring lands west of the Mississippi River that effected the Louisiana Purchase.
Lewis, Clark I want you to go out and explore land
On May 14, 1804, Clark and the Corps joined Lewis in St. Charles, Missouri and headed upstream on the Missouri River in the keelboat and two smaller boats at a rate of about 15 miles per day.
Lewis and Clark surveyed was occupied by Native Americans. The Corps encountered around 50 Native American tribes including the Shoshone, the Mandan, the Minitari, the Blackfeet, the Chinook and the Sioux.
They exchanged goods and presented the tribe’s leader with a Jefferson Indian Peace Medal – a coin engraved with the image of Thomas Jefferson on one side and a picture of two hands beneath a tomahawk and a peace pipe with the words, “Peace and Friendship” on the other.
At Fort Mandan, Lewis and Clark met French-Canadian trapper Toussaint Charbonneau and hired him to be a interpreter. They allowed his pregnant Shoshone Indian wife Sacagawea to join him on the expedition.
Lewis and Clark returned to Washington, D.C., in the fall of 1806 and shared their experiences with Jefferson.