Democratic
Missouri › Missouri House of Representatives · State legislature · November 3, 2026 · Updated Oct 16, 2026
Missouri House District 105
Projected flip: Republican-held seat, Democrats favored (78%).
Clayton is favored to win: Clayton wins in about 4 of every 5 simulations.
Clayton (D)
78%
chance of winning
Wellenkamp (R)
22%
- Average margin
- D+5.7
- 80% of outcomes
- R+4 to D+15
- Partisan lean
- D+1
- Polls
- No pollsmodel only
Projected flip: Republican-held seat, Democrats favored (81%).
Clayton is clearly favored to win: Clayton wins in 4 of every 5 simulations.
Clayton (D)
81%
chance of winning
Wellenkamp (R)
19%
- Average margin
- D+8.1
- 80% of outcomes
- R+5 to D+21
- Partisan lean
- D+1
- Polls
- No pollsmodel only
Range of outcomes
Final margin across our simulations; the white dashes mark the middle 80%.
The candidates
RepublicanIncumbent
Colin Wellenkamp
What goes into the forecast
Every ingredient's estimate of the final margin.
- National environment
- D+9.5Election Day forecast
- Missouri state offices
- +0.6Polls for governor, statewide and legislative races · details
- Environment here
- D+10.1Used 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) | -0.21 |
| Elected-experience edge | -0.67 |
| First-term incumbent | 0 |
| Seat's last result vs. expectation | -4.63 |
| Incumbent's last result vs. expectation | -4.63 |
Polls
No public polls of this race. The forecast relies on fundamentals and on polling of similar places in the state.
The district
Lean D+1: 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
- 34,685
- People per km²
- 1,250
- Adults with a B.A.+
- 41%
- White, no degree
- 48%of adults
- White 77%
- Hispanic 6%
- Black 8%
- Asian 4%
- Other / multiracial 5%
American Community Survey 2020–2024, aggregated from census tracts.
Past results
Results in the same-numbered district; earlier elections may have used different lines.
2024
15,458 votes · R+5.8✓ Colin Wellenkamp (R)52.9%
Ron Odenthal (D)47.1%
2024 President Vote in this district
16,085 two-party votes · D+1.1 · D+2.6 vs. the nation✓ Kamala Harris (D)50.6%
Donald Trump (R)49.4%
2022
10,951 votes · R+0.9✓ Adam Schwadron (R)49.3%
Cindy Berne (D)48.4%
Michael Carver (L)2.2%
2020 Earlier district lines
21,876 votes · R+16.1✓ Phil Christofanelli (R)58.1%
Christine Hyman (D)41.9%
2020 President Vote in this district
15,506 two-party votes · D+2.1 · R+2.4 vs. the nation✓ Joe Biden (D)51.1%
Donald Trump (R)48.9%
2016 President Vote in this district
14,657 two-party votes · R+11.0 · R+13.3 vs. the nation✓ Donald Trump (R)55.5%
Hillary Clinton (D)44.5%