Illinois 9th District
Currently held by a Democrat · open seat
- Projected margin
- D+47.1
- 80% range
- D+34.6 to D+59.7
- Partisan lean
- D+38.6
- Uncertainty multiplier
- 2.01×
The 80% range comes from 200,000 simulations in which this race’s error is correlated with every other race through the national, state and demographic layers.
- Polling average
- no polls
- Fundamentals
- D+47.3
- Blended
- D+47.3
- Similar-race shift
- −2.6
No public polling of this matchup. The forecast rests on fundamentals plus the polling residuals of demographically and politically similar races — which is the normal case: most of the 435 House seats are never polled.
- Partisan lean
- D+38.6
- Elasticity
- 1.00
- Incumbency
- 0.0
- Candidate experience
- 0.0
- Fundraising
- +4.1
- National environment
- D+7.1
- Expected margin
- D+49.9
- 2024 margin
- D+37.0
- 2020 margin
- D+42.1
- Shift 2020 → 2024
- R+5.0
- Votes cast, 2024
- 351,559
Presidential results reaggregated onto the 2026 district lines. This is where the seat’s partisan lean comes from, and it carries most of the forecast in a race nobody has polled.
- Population
- 607,511
- Median age
- 49.1
- Median household income
- $89,100
- Bachelor’s degree or higher
- 55%
- White
- 62%
- Black
- 10%
- Hispanic
- 12%
- Asian
- 16%
Used to find demographically similar districts, so a race with no polling can borrow the polling error of races that look like it.
| Candidate | Party | Raised | Cash on hand |
|---|---|---|---|
| Daniel Biss | DEM | $2.9M | $262k |
| Dongbo Su | REP | $24k | $0 |
Receipts across the cycle, from FEC bulk filings. The model uses the ratio between the two sides rather than either total, and weights it lightly — money follows a competitive race at least as much as it causes one.