Doubling the size of the U.S. provided more opportunities for poor families, but the territory needed to be explored and mapped first.

Jefferson hires Meriwether Lewis and William Clark to lead the expedition. They started in May 1804 from Missouri, traveling to find the origin. The goal was to find a  water route to the Pacific Ocean. Many botany, zoology, and navigation experts came with Lewis and Clark. The president was funding the expedition, and he wanted to find out more about the animals and plants living in the territory.

Fort Mandan was the winter quarters for Lewis and Clark’s expedition. During the winter, Lewis and Clark caught up on their maps and classifications. One important thing happened at Fort Mandan, they met Tousian Charbonneau and his wife, Sacagawea. Sacagawea joined the party and became a translator for the crew.

At the end of the winter, they sent back a boat filled with maps and journals to Jefferson. And the group traveled toward Montana and Idaho.

After wintering in Fort Clatsop, the expedition planned on going back to Washington by boat. Instead, they decided to explore more land. Lewis and Clark split up the group and each one took half the travelers with him.

Then they reunited just below Yellowstone.