Longtime state Sen. James Clayborne of Belleville will face a challenger, Swansea attorney Katherine Ruocco, in the general election.
St. Clair County Clerk Tom Holbrook also will have a challenger, James Rubush.
Clayborne, a Democrat, has served almost 20 years in the Senate. He is the majority leader for the Senate Democrats.
Ruocco, a Republican, has a law practice in St. Louis and is a trustee on the Swansea Village Board.
Unseating Clayborne would be a challenge. The most recent quarterly report for his campaign committee, from the end of March, showed that he had about $520,000 available in his election fund.
Rubush is one of three Republican candidates who recently filed petitions to challenge incumbent Democrats holding St. Clair County posts. The challengers were chosen during a caucus of the county's Republican Party.
The established political parties had until the end of the day Monday to slate candidates for the November election. The political parties had the opportunity to slate candidates for office if the party had no candidates in the primary election.
The other candidates include James Wilson seeking a seat on the county's Board of Review and Fred Boch seeking to represent District 23, part of O'Fallon and Shiloh, on the County Board.
Rubush, of O'Fallon, is a retired lieutenant colonel with the Air Force and involved with multiple community organizations.
Holbrook, of Belleville, served as a state representative from 1995 to 2011, then resigned to accept an appointment to lead the state's Pollution Control Board. Holbrook accepted an appointment to the County Clerk's post in June 2013 after former County Clerk Bob Delaney resigned amid allegations of racial and sexual harassment from county employees.
Wilson is challenging Charlotte Moore, of East St. Louis, for her seat on the Board of Review. The Board of Review hears appeals from property owners who believe their property is improperly assessed, which determines the amount of real estate taxes on the property.
Wilson is a residential real estate appraiser and serves as the St. Clair Township Assessor.
Boch, of O'Fallon, seeks to unseat County Board member Dennis Renner, of O'Fallon. Renner defeated Bill Blair II, a Republican, to earn his seat in 2012. Renner is retired from the St. Clair County Highway Department and a former member of the O'Fallon City Council.
Boch is a real estate broker with Coldwell Banker Brown Realtors in O'Fallon and a former director of mental health services with the Clinton County Rural Health Clinic in Breese.
The other contested St. Clair County races include:
* County Treasurer -- Democratic incumbent Charles Suarez, of Swansea, faces Republican challenger Rodger Cook, of St. Libory.
* District 1 -- Incumbent County Board member Robert Allen Jr., of Fairmont City, faces Republican Rob Dorman, of Collinsville, in their campaigns to represent Fairmont City and parts of Caseyville and Collinsville.
* District 12 -- Incumbent Angela Grossmann-Roewe, a Democrat from Belleville, faces challenger Guy N. Don Carlos, a Republican from Belleville. The seat represents part of eastern Belleville.
* District 27-- Incumbent Kenneth G. Sharkey, a Democrat, faces challenger Matthew R. Stirrup, a Republican, to represent parts of Fairview Heights and O'Fallon. Both candidates are from Fairview Heights.
* District 28 -- Incumbent Joseph J. Kassly Jr., a Democrat, faces challenger Timothy L. Buchanan, a Republican, to represent parts of Fairview Heights and Swansea. Both candidates are from Swansea.
St. Clair County Sheriff Rick Watson and County Assessor Jennifer Gomric-Minton, both Democrats, are currently running unopposed to retain their posts.
In Madison County, most county races are uncontested. Incumbent Sheriff Bob Hertz lost to his primary challenger, Glen Carbon Police Chief John Lakin. There was no Republican candidate in the primary, and Madison County Republican Party chairman Chris Slusser confirmed that they have decided not to slate a candidate to oppose Lakin in the general election.
Incumbent county clerk Debbie Ming-Mendoza (D-Granite City) is being challenged by Republican Stephen Adler, and incumbent treasurer Kurt Prenzler (R-Edwardsville) is being challenged by Democrat Marleen Suarez.
Ming-Mendoza said that Democrat Jared Hartsock has filed for County Board District 14 to challenge Republican Tom McRae; and Republican Chris Doucleff has filed for County Board District 10 to challenge Democrat Bruce Malone. No other post-primary filings have yet been recorded, she said.
Independent candidates and those from new political parties have between June 16 and June 23 to file candidate petitions.