Sacagawea was a member of the Shonshone Indian Tribe. Her father was chief of the tribe. During the summer, the tribe lived in the Rocky Mountains in the west. Sacagawea's older brother taught her how to swim and to find her way through the mountains using landmarks. She also learned how to gather food and use plants for healing. In the fall, the tribe moved east to the plains to hunt buffalo. During their travels, they met other Indians and Sacagawea learned how to use sign language as a means of communication.

When Sacagawea was about 10 years old, she was with her people on a buffalo hunt and was captured by another Indian tribe. They took her far away to their village near Mandan on the Missouri River in what is now North Dakota. Sacagawea lived at the Mandan Indian village for several years. In 1804 she was sold to a French trapper and became his wife. This was the year that the explorers Lewis and Clark started up the Missouri River from St. Louis on their expedition to the west. In October they arrived at the Indian village where Sacagawea had lived and they spent the winter there.

Lewis and Clark hired Sacagawea's husband as an interpreter. When they learned that Sacagawea had been a member of the Soshone Indian tribe and had lived in the Rocky Mountains, they asked that she also join the expedition when it continued in the spring. In February 1805, Sacagawea gave birth to a baby boy. Two months later, with her son on her back and her husband at her side, she set out with the expedition to the west. As they traveled along the Missouri River they met several Indian tribes. When they neared the Rocky Mountains, they met a band of Shoshone Indians and Sacagawea was reunited with her people. Her brother was now chief of the tribe. She helped the explorers trade gifts to her people for horses and supplies that they needed to cross the mountains. They were also given a guide.

The crossing took about a month and was very hazardous. The weather was bad, food was scarce, and many people, including Sacagawea, were very sick. The explorers built a fort near the Pacific Ocean and spent the winter there. In March 1806, the expedition started back to St. Louis. Sacagawea did not see her people along the way. When they reached the Mandan Indian village, Sacagawea and her son stayed there with her husband and the expedition continued to St. Louis.

About 5 years later, Sacagawea and her husband took their son to St. Louis and left him in the care of Captain Clark to be educated. Her husband soon went back to trapping and Sacagawea returned to her people in the Rocky Mountains. Sacagawea's son became a guide for western travelers and eventually returned to the Shoshone tribe to live with his mother's people.

It is not known for sure when Sacagawea died. Some say she died on the Missouri River about 1811. An entry in Captain Clark's journal of 1825-1828 lists her as dead. Others say she died in Wyoming in 1884. Whichever it may be, she was a courageous young women. With her help, the sucess of the Lewis and Clark Expedition enabled the United States to expand its territory to the west.

Monuments and memorials have been erected in honor of Sacagawea and many places have been named after her including a river, a peak, a mountain pass, a lake, and a state park. In February 2000, the U.S. Mint released a new dollar coin featuring her image.