During the late 1600s and 1700s, the American frontier slowly shifted from the East Coast to the Appalachian Mountains to the Mississippi River.
In 1803, overnight, the territory of the United States almost doubled in size with the Louisiana Purchase.
This area, extending from the Mississippi River to the Rockies, was sold to the U.S. government by the French, who had recently acquired it from Spain.
Anglo men set out to explore this new territory, and Anglo women soon joined them.
The big westward push, when thousands of people crossed the Great Plains, came later, in the 1840s and 1850s.