It yielded a certain profit; it shaped the character of the men who carried it on.

But what is yet more important, it greatly influenced the country which lay back of the border on the Missouri River.

It called yet more men from the eastern settlements to those portions which lay upon the edge of the Great Plains.

There crowded yet more thickly, up to the line between the certain and the uncertain, the restless westbound population of all the country.
If on the south the valley of the Arkansas led outward to New Spain, yet other pathways made out from the Mississippi River into the unknown lands.

The Missouri was the first and last of our great natural frontier roads.