Lewis was born in Virginia in 1774 and lived there until his 10th birthday, when his family moved to Georgia. He was eventually sent back to Virginia to finish his education. When he was 20, he joined the Virginia militia. This was just the beginning of his military careerhe eventually enlisted in the regular army and stayed there for several years, eventually becoming a captain.
In 1801, President Thomas Jefferson chose Lewis as his personal secretary. The two worked closely together, planning Lewis's upcoming expedition. Lewis even traveled to Philadelphia to learn map-making skills so that he could keep a record of the new lands he saw.
Three years later, Lewis was ready to go. He chose Clark as his partner, and on May 14, 1804, the two leaders and their crew set off for uncharted land. They passed through what is now known as Kansas City, Missouri, and Omaha, Nebraska. Crossing the Rocky Mountains led the team to Portland, Oregon, and finally, to the Pacific Ocean.
The journey home took Lewis and his men about six months. When he finally returned, Lewis was awarded a large plot of land as thanks for leading the trip. He discovered important information about what kinds of plants, animals, mountains, and rivers were in the western part of the United States. Lewis died in 1809.