Illinois' 4th Congressional District remains a solidly Democratic stronghold, with trader consensus assigning 93.3% implied probability to the Democratic Party after Patty Garcia secured the nomination in the March 17 primary as the handpicked successor to retiring Rep. Jesús "Chuy" García. The district's heavy partisan lean—reflected in overwhelming Democratic margins in recent presidential and midterm races—drives this commanding position, bolstered by Garcia's fundraising edge and endorsements from progressive groups, while Republican nominee Lupe Castillo trails in resources and name recognition. No major developments have emerged in the past 30 days to alter sentiment ahead of the November 3 general election. Upsets would require a Democratic scandal, national GOP midterm wave, or unexpected independent surge.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedIL-04 House Election Winner
IL-04 House Election Winner
$33,061 Vol.
$33,061 Vol.
Democratic Party
93%
Republican Party
6%
$33,061 Vol.
$33,061 Vol.
Democratic Party
93%
Republican Party
6%
A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources.
This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).
Market Opened: Jan 28, 2026, 11:08 AM ET
Resolver
0x2F5e3684c...A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources.
This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).
Resolver
0x2F5e3684c...Illinois' 4th Congressional District remains a solidly Democratic stronghold, with trader consensus assigning 93.3% implied probability to the Democratic Party after Patty Garcia secured the nomination in the March 17 primary as the handpicked successor to retiring Rep. Jesús "Chuy" García. The district's heavy partisan lean—reflected in overwhelming Democratic margins in recent presidential and midterm races—drives this commanding position, bolstered by Garcia's fundraising edge and endorsements from progressive groups, while Republican nominee Lupe Castillo trails in resources and name recognition. No major developments have emerged in the past 30 days to alter sentiment ahead of the November 3 general election. Upsets would require a Democratic scandal, national GOP midterm wave, or unexpected independent surge.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated



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