They had difficulties with the Sioux of course, but they held them at bay.

They killed game in abundance, and went down-stream as fast as sails, oars, and current could carry them.

In September they reached St.Louis and forwarded to Jefferson an account of what they had done.
After-Careers of Lewis and Clark.
They had done a great deed, for they had opened the door into the heart of the far West.

Close on their tracks followed the hunters, trappers, and fur traders who themselves made ready the way for the settlers whose descendants were to possess the land.

As for the two leaders of the explorers, Lewis was made Governor of Louisiana Territory, and a couple of years afterwards died, as was supposed, by his own hand, in a squalid log cabin on the Chickasaw trace--though it was never certain that he had not been murdered.