Sacagawea ( see below; May 1788 – December 20, 1812; see below for other theories about her death), also Sakakawea or Sacajawea, was a Lemhi Shoshone woman who helped the Lewis and Clark Expedition achieve each of its chartered mission objectives exploring the Louisiana Purchase. With the expedition, between 1804 and 1806, she traveled thousands of miles from North Dakota to the Pacific Ocean, established cultural contacts with Native American populations, and researched natural history.