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This Day in American History

December 3

1 historic event on this date

Historical1818

Illinois Admitted to the Union

Illinois was admitted as the 21st state of the United States. The state would play a pivotal role in national history as the political home of Abraham Lincoln and a key state in the debates over slavery and expansion.

Why It Matters

Illinois's admission expanded the union and its political influence would prove crucial in the election of Lincoln and the preservation of the Union during the Civil War.

Explore the Principles Behind the History

Every event in American history connects to the founding principles. Discover the ideas that shaped these moments.

View the 28 Founding Principles