Illinois 4th — House 2026 Rep Primary
The Illinois 4th — House rep primary is scheduled for March 17, 2026. Lupe Castillo is running unopposed. No public polling is available for this race, so the forecast leans on fundraising, endorsements, candidate profiles, and historical results.
Current win probabilities
- Lupe Castillo — 100%
Probabilities update daily from polls, fundraising, endorsements, and historical results.