Final answer:
In 1820, approximately seventy thousand people lived west of the Appalachian Mountains.
Step-by-step explanation:
In 1820, it is estimated that seventy thousand people lived west of the Appalachian Mountains. The westward expansion in the United States resulted in an increasing number of settlers moving beyond the mountains in search of new opportunities and land. However, it is important to note that this number would grow significantly in the following decades as more people migrated westward.
Learn more about Westward expansion in the United States