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

The correct answer is Illinois because it was not one of the original 13 states that formed the United States. The original 13 states were all located along the east coast and included Massachusetts, Virginia, New Jersey, and others that established their independence from British rule in the late 18th century. Illinois, on the other hand, was admitted to the Union much later, in 1818, making it part of the western expansion of the United States rather than its initial formation. This distinction is crucial for understanding the early political and historical landscape of the United States.