Staggered Senate
Senators serve four-year terms; half the seats are on the ballot each election.
Iowa › Iowa State Senate · November 3, 2026 · Updated Oct 16, 2026
Iowa State Senate District 1
Drey is clearly favored to win: Drey wins in 4 of every 5 simulations.
Drey (D)
80%
chance of winning
Prosch (R)
20%
- Average margin
- D+6.5
- 80% of outcomes
- R+4 to D+17
- Partisan lean
- R+9
- Polls
- No pollsmodel only
Flip risk: Democratic-held seat, a toss-up (58% chance it changes parties).
A toss-up: each side wins about half the simulations.
Drey (D)
42%
chance of winning
Prosch (R)
58%
- Average margin
- R+1.9
- 80% of outcomes
- R+14 to D+11
- Partisan lean
- R+9
- Polls
- No pollsmodel only
How this race is decided
Range of outcomes
Final margin across our simulations; the white dashes mark the middle 80%.
The candidates
DemocraticIncumbent
Catelin Drey
- Experience
- State legislature
Republican
Christopher Prosch
What goes into the forecast
Every ingredient's estimate of the final margin.
- National environment
- D+9.5Election Day forecast
- Iowa state offices
- +1.4Polls for governor, statewide and legislative races · details
- Environment here
- D+10.9Used by the fundamentals
- Swing reaching this office
- 58%Of a shift in the environment, from past legislative races since 2016
- Midwest adjustment
- +0.3How legislative races in the region have run against lean and environment lately
Each estimate is a margin before national and statewide uncertainty is simulated. Horizon blends polls, fundamentals and a little of the similar-places estimate, weighting each by how precise it is; Pulse uses polls and similar places only.
Fundamentals inputs
| Incumbency (+1 D, −1 R) | 1 |
| Fundraising edge (log ratio of individual money) | 1.57 |
| Elected-experience edge | 0.67 |
| First-term incumbent | 0 |
| Seat's last result vs. expectation | 1.8 |
| Incumbent's last result vs. expectation | 0 |
Polls
No public polls of this race. The forecast relies on fundamentals and on polling of similar places in the state.
The district
Lean R+9: how much more Democratic or Republican than the nation it votes for president.
Presidential vote
Precinct results re-aggregated to the current district lines.
Who lives here
- Population
- 63,312
- People per km²
- 219
- Adults with a B.A.+
- 22%
- White, no degree
- 49%of adults
- White 59%
- Hispanic 26%
- Black 5%
- Asian 3%
- Other / multiracial 8%
American Community Survey 2020–2024, aggregated from census tracts.
Past results
Results in the same-numbered district; earlier elections may have used different lines.
2025 special
7,629 votes · D+10.5✓ Catelin Drey (D)55.2%
Christopher Prosch (R)44.7%
2024 President Vote in this district
21,339 two-party votes · R+11.6 · R+10.1 vs. the nation✓ Donald Trump (R)55.8%
Kamala Harris (D)44.2%
2022
13,986 votes · R+10.3✓ Rocky de Witt (R)55.1%
Jackie Smith (D)44.7%
2020 President Vote in this district
23,442 two-party votes · R+2.9 · R+7.4 vs. the nation✓ Donald Trump (R)51.4%
Joe Biden (D)48.6%
2018 Earlier district lines
21,629 votes · Uncontested by the other party✓ Zach Whiting (R)98.2%
Writein (—)1.8%
2016 President Vote in this district
21,859 two-party votes · R+6.7 · R+8.9 vs. the nation✓ Donald Trump (R)53.3%
Hillary Clinton (D)46.7%