Back in 1800 before the epic trip, the US population was 5.3 million. Ten years later, it increased to 7.2 million — a 36 percent increase. As shown in the following maps, this growth continued, and started moving west, adding territories and states along the way.
US Growth the First 100 Years After Lewis and Clark Explored
The population of the northeast region — once the focal point of the US — shrank by 1.1 percent from 2000 to 2010. The Midwest also saw a decline in population (1.2 percent). Meanwhile, the South and the West grew, 1.5 percent and 0.8 percent respectively.