On the new maps the country now showed as part of the United States; but the Indians who alone inhabited it were as little affected by the transfer as was the game they hunted.
Need for its Exploration.
Even the Northwestern portion of the land definitely ceded to the United States by Great Britain in Jay's treaty was still left in actual possession of the Indian tribes, while the few whites who lived among them were traders owing allegiance to the British Government.

The head-waters of the Mississippi and the beautiful country lying round them were known only in a vague way; and it was necessary to explore and formally take possession of this land of lakes, glades, and forests.
Beyond the Mississippi all that was really well known was the territory in the immediate neighbourhood of the little French villages near the mouth of the Missouri.

The creole traders of these villages, and an occasional venturous American, had gone up the Mississippi to the country of the Sioux and the Mandans, where they had trapped and hunted and traded for furs with the Indians.

At the northern most points that they reached they occasionally encountered traders who had travelled south or southwesterly from the wintry regions where the British fur companies reigned supreme.

The headwaters of the Missouri were absolutely unknown; nobody had penetrated the great plains, the vast seas of grass through which the Platte, the Little Missouri, and the Yellowstone ran.