This coin was first produced in 2000 to replace the Susan B. Anthony dollar that never really caught on. In an attempt to address consumer complaints the composition and appearance were dictated by Public Law 105-124. It was hoped that the distinctive gold color and smooth edge would distinguish it from the quarter dollar that it so closely resembled in size (26.5 mm vs 24.3mm).
The design for the coin resulted from what was then a unique process that included input from many constituencies including congress, various artistic agencies, collector groups and historians. The process is well documented at the official US mint site
The design process eventually settled on an obverse design showing ¾ profile portrait of Sacagawea, a Shoshone Indian guide, who accompanied Meriwether Lewis and William Clark on their Journey of Exploration across North America in 1804-6. In another first for American coinage the portrait on the obverse show Sacagawea carrying Jean Baptiste, her infant son strapped to her back. Six months pregnant when she joined the expedition, Sacagawea gave birth to the boy early in the journey and carried him to the end. The design was submitted and executed by Glenda Goodacre
The reverse design is a slightly more traditional motif. It features a soaring eagle encircled by 17 stars. The stars represent the 17 state in the Union at the start of the 1804 Lewis and Clark expedition. The reverse design was executed by mint engraver Thomas D. Roger Sr.
The Obverse design continues as part of the Native American Dollar series begining in 2009. As a condition of this program the reverse design will be changed on a yearly basis.