Vacant Otis F. Glenn Republican The 1928 United States Senate special election in Illinois took place on November 6, 1928.

[1] The election was held due to the U.S. Senate's refusal to seat 1926 election winner, Republican Frank L. Smith, due to allegations of election fraud.

Chicago mayor William Hale Thompson backed Smith for Senate, while Charles S. Deneen, who held Illinois' other U.S. Senate seat, backed Glenn.

Thompson and Deneen controlled rival factions of the state's Republican Party.

[6][7] Thompson's faction was vastly dominant at the time.