Sacagawea (Hidatsa Tsakákawia, "bird woman") was the Lemhi Shoshone woman who, at approximately 16 and carrying her infant son, served as interpreter and guide to the Lewis and Clark Expedition (1804-1806) on its journey from the Mandan villages to the Pacific Ocean and back. Her presence and that of her newborn signaled the expedition's peaceful intent to every tribe they encountered — Clark wrote that no party with a woman could be considered a war party. She is depicted on the US Sacagawea dollar coin minted since 2000, and has more statues across the United States than any other woman.
Subject of Anna Lee Waldo's Sacajawea (1979) and many history books.
Sacagawea does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Sacagawea reduce to 7, The Seeker. This is a traditional interpretive system, not a factual claim about the name.