When Sacagawea was born, George Washington was president, and the country was just 13 states along the Atlantic Coast. That would quickly change.
In 1801, Thomas Jefferson became president. He dreamed of a country that stretched from the Atlantic to the Pacific. Native Americans had lived on this land for thousands of years. Jefferson didn’t give them much thought. Who did he think about? The European countries that claimed various parts of the West. They worried him. Especially because Spain had just sold France a huge piece of land called Louisiana. The key port of New Orleans was at the southern tip of this land. Jefferson wanted to get the French leader, Napoléon, to sell New Orleans to the U.S. As it turned out, Jefferson got way more than he bargained for.

▲ Napoléon wanted to build an empire in Europe and beyond. But he didn’t have the money for wars in both Europe and America. To Jefferson’s surprise, Napoléon sold New Orleans. He also sold the U.S. all the rest of the Louisiana Territory. The price was $15 million (about four cents per acre). With this 1803 purchase, the U.S. doubled its size.

◀ It wasn’t only France that worried Jefferson. Spain, Russia, and Britain all claimed land in the U.S. and Canada. In 1793, Scotsman Alexander Mackenzie had traveled from central Canada all the way to the Pacific Coast. He claimed the Pacific Northwest for Britain. Jefferson needed to get the U.S. into the West—and fast!

▲ Jefferson chose his secretary, Meriwether Lewis, to explore the new territory. Lewis picked William Clark to be co-captain. Lewis and Clark had served together in the army. They put together a group of volunteers and gathered supplies. They planned to sail up the Missouri River as far as possible. Then they would head for the Pacific on land. Along the way, they would make maps. They would be friendly with the Native Americans they met. They would also gather examples of animal and plant life. And of course, they would write about what they saw.


◀ It was too hard to travel during the winter. Lewis and Clark decided to camp near the friendly Mandan and Hidatsa villages. That is where Sacagawea and Charbonneau lived.

▲ Corps of Discovery Expedition
On May 14, 1804, the Lewis and Clark expedition set out from Wood River, Missouri. It was officially known as the Corps of Discovery. There were about 40 members. They included Clark’s slave, York, and Lewis’s huge Newfoundland dog, Seaman.