electionsmcp › races › Iowa State Senate District 8
Iowa State Senate District 8
The current officeholder, the 2024 result, and a precinct-level model you can run yourself — built from how Iowa actually voted.
Model Iowa State Senate District 8 →
Current officeholder
Mark Costello Republican
2024 result
Republican R+41.2
2024 votes cast
35,501
Office
State Senate
Precinct results — 2024 general
43 precincts reported in Iowa State Senate District 8's 2024 general election. The twenty largest:
| Precinct | Winner | Margin | Votes |
|---|---|---|---|
| 19155-CB 22 | Republican | R+30.3 | 2,108 |
| 19155-GARNER | Republican | R+39.8 | 1,981 |
| 19129-Oak/St. Mary | Republican | R+45.9 | 1,784 |
| 19155-UNDERWOOD | Republican | R+41.9 | 1,743 |
| 19155-TREYNOR | Republican | R+54.0 | 1,701 |
| 19155-CRESCENT | Republican | R+33.0 | 1,601 |
| 19155-LEWIS 2 | Republican | R+37.6 | 1,520 |
| 19129-Malvern/Tabor/Silver Creek/Center/Rawles | Republican | R+39.1 | 1,449 |
| 19155-LEWIS 1 | Republican | R+31.5 | 1,282 |
| 19085-Precinct #8 Logan | Republican | R+43.7 | 1,258 |
| 19085-Precinct #10 Missouri Valley | Republican | R+31.0 | 1,168 |
| 19155-OAKLAND | Republican | R+45.8 | 1,104 |
| 19085-Precinct #6 Woodbine | Republican | R+43.5 | 1,055 |
| 19071-Sidney | Republican | R+43.2 | 1,018 |
| 19071-Green/Riverside/Scott | Republican | R+47.4 | 989 |
| 19155-CARSON | Republican | R+48.0 | 853 |
| 19129-Glenwood Ward 3 | Republican | R+23.9 | 830 |
| 19129-Glenwood Ward 2 | Republican | R+27.1 | 768 |
| 19129-Glenwood Township | Republican | R+34.0 | 755 |
| 19085-Precinct #9 St John | Republican | R+42.0 | 734 |
All 43 precincts are modelable — open the race in the simulator and drill to precinct grain.
Find your district
Enter a ZIP code or a district (e.g. NC-4) to find your U.S. House district and who represents it.
Model Iowa State Senate District 8 in five steps
- Set the candidates. Name the contenders for the Iowa State Senate District 8 (or keep the generic Democrat / Republican defaults). The map starts from real 2024 results in every precinct.
- Apply a swing. Move vote share statewide, or by demographic cohort, with a slider. The map and the running tally recompute instantly.
- Model turnout. Mobilize or depress turnout for any group — turnout and persuasion are modeled separately, the way a real campaign thinks about them.
- Drill to precincts. Zoom from the state down to individual precincts and override any of them by hand.
- Roll up & share. Roll the result up to chamber control, then publish a shareable, frozen link to your scenario.
Open Iowa State Senate District 8 in the simulator →
Frequently asked
Who represents Iowa State Senate District 8?
Mark Costello (Republican) currently holds this State Senate seat.
What was the 2024 result in Iowa State Senate District 8?
R+41.2 — 10,432 Democratic, 25,069 Republican, of 35,501 votes cast.
Can I model this race myself?
Yes — open it in the electionsmcp simulator and model vote-share swing and turnout from the real 2024 baseline, down to the precinct, then roll it up to chamber control.