Illinois Territory's at-large congressional district

Illinois Territory's at-large congressional district was a congressional district that encompassed the entire Illinois Territory.

The district elected a non-voting delegate to the United States House of Representatives.

On April 18, 1818, Congress passed an act that enabled the people of Illinois Territory to begin the process of forming a state.

As part of that act, Illinois Territory was reduced in size to the boundaries of the present state.

The state of Illinois was accepted into the Union on December 3, 1818.