The dominion of the United States was now extended across the entire continent of North America, reaching from the Atlantic to the Pacific.

The Territory of Oregon was already ours.
This momentous transfer took place one hundred years ago, when almost nothing was known of the region so summarily handed from the government of France to the government of the American Republic.

Few white men had ever traversed those trackless plains, or scaled the frowning ranges of mountains that barred the way across the continent.

There were living in the fastnesses of the mysterious interior of the Louisiana Purchase many tribes of Indians who had never looked in the face of the white man.
Nor was the Pacific shore of the country any better known to civilized man than was the region lying between that coast and the Big Muddy, or Missouri River.

Spanish voyagers, in 1602, had sailed as far north as the harbors of San Diego and Monterey, in what is now California; and other explorers, of the same nationality, in 1775, extended their discoveries as far north as the fifty-eighth degree of latitude.