Illinois elected its United States Representative at-large on a general ticket upon achieving statehood December 3, 1818. Although the practice was first ended in 1830, it was revived several times, so that there would be at least one seat elected at large, in addition to elections in single-member districts. It last elected a US Representative at large in 1946. The district has been obsolete since.
From statehood to 1833, Illinois had only one congressional district, and therefore it was at-large.
From 1863 to 1873 there was one at-large seat in addition to the districted seats.
From 1893 to 1895, there were two at-large seats in addition to the districted seats.
Two at-large seats were re-established March 4, 1913. From that date to January 3, 1943, there were two at-large seats, which was reduced to one seat from 1943 to 1949. Representation by districts also continued during this period. The at-large seat was abolished effective January 3, 1949.