The beginning of 1803, the United States of America extended only to the Mississippi River, and even then the young nation did not include all the land east of the great waterway.
Beyond the Mississippi, the land - the vast deserts, thick forests, and towering mountains - was claimed by Spain, France, and Great Britain. And it was occupied largely by various Indian tribes.
President Thomas Jefferson had always wanted to know what was out there, what lay between the Mississippi and the great ocean. He had spent years nurturing the idea of an expedition (there were even several attempts) to map the area with a number of objectives in mind, some scientific and commercial, others political and expansionist.
Jefferson envisioned a nation that would grow beyond the original thirteen colonies and espoused the principle that new states should come into the union on an equal footing with the older states, with full rights, wrote Dumas Malone in Jefferson the President: First Term, 1801 - 1805,the fourth volume of his life of Jefferson. "No one more than he deserves to be described as the architect of orderly expansion," Malone said.
In late 1802, Jefferson was in a position to satisfy his curiosity about the land beyond the Mississippi and was preparing to ask Congress for the money to finance an expedition. However, his pursuit of funds for what became the Lewis and Clark expedition would have to be made carefully, so as not to arouse the suspicions of the other powers that claimed the land as their own.
Meanwhile, the President's attention had been diverted to the issue of control of the port of New Orleans, the gateway to the Mississippi River, which had become an important commercial thoroughfare for what was then the western United States.
Why did Southerners support the Kansas-Nebraska Act? The Popular Sovereignty clause in the Act meant the territories might allow slavery and enter the Union as slave states. The population increased greatly as settlers flooded into the territory from both free states and slave states.
