Republican Dwight Kay of Glen Carbon has defeated incumbent Democrat Jay Hoffman of Collinsville in the 112th House District, 19,473 to 18,102.
The district encompasses parts of Madison and St. Clair counties. In Madison County, Kay topped Hoffman 16,592 votes to Hoffman's 14,961 votes.
In St. Clair County, however, Hoffman topped Kay 3,141 to 2,881.
Hoffman has held the seat since 1991.
He raised more than $480,000 since the beginning of July, on top of nearly $500,000 he had in reserve.
Hoffman is an attorney of counsel with the LakinChapman firm in Wood River.
Kay, who is a vice president of Edwardsville-based Cassens Transport, raised more than $400,000 since the beginning of July. The House Republican Organization and the Illinois Republican Party helped finance his campaign.