Which of the following states was not one of the original 13 states?

Illinois was not one of the original 13 states. The original 13 states were those that declared independence from Great Britain in 1776 and subsequently formed the United States. These included states like Delaware, Maryland, and Georgia, all of which played significant roles in early American history.

Illinois, however, was not established as a state until later, entering the Union as the 21st state in 1818. This detail is crucial for understanding U.S. history as it highlights the growth and expansion of the nation beyond the original colonies established along the East Coast.