United States congressional delegations from Illinois

These are tables of congressional delegations from Illinois to the United States House of Representatives and the United States Senate.

List of members of the Illinois United States House delegation, their terms in office, district boundaries, and the district political ratings according to the CPVI. The delegation has a total of 18 members, with 11 Democrats and 7 Republicans.

Tables showing membership in the Illinois federal House delegation throughout history of statehood in the United States.

The Illinois Territory was established on March 1, 1809.

Part of the area of Illinois Territory became the State of Illinois on December 3, 1818.

From statehood in 1818, until the addition of two seats in 1833, Illinois had one Representative, elected at-large statewide.

Illinois gained one seat in 1881 and two more in 1891, but didn't redistrict until 1893.

Tables showing membership in the Illinois federal Senate delegation throughout history of statehood in the United States.

As of January 2017^[update], there are six former U.S. Senators from the U.S. State of Illinois who are currently living at this time, all from Class 3.

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