Mark Costello
State Senator, Iowa Senate District 8 · Republican
OfficeholderNot running in 2026
Ballot status source: Incumbency rule: Iowa Senate even-numbered District 8 — four-year term, next election 2028 · read Sep 24, 2026
Sources (3)
- Incumbency rule: Iowa Senate even-numbered District 8 — four-year term, next election 2028
- no IA-SD-08 contest on the Iowa Secretary of State — Candidate List, November 3, 2026 General Election
- role and held seat unchanged
The District
What Iowa Senate District 8 covers
Covers all of Harrison County, Fremont County and Mills County; part of Pottawattamie County.
Includes Dunlap, Glenwood, Hamburg, Malvern, Missouri Valley, Oakland, Sidney, Tabor, Walnut, Woodbine, Anderson, Bartlett and 33 more.
43 precincts · District lines: State senate lines: U.S. Census Bureau (1:500,000 cartographic boundary) · Precinct lines: Iowa Legislative Services Agency, Iowa Precincts (as of the 2022 reprecincting) statewide layer (services.arcgis.com/vPD5PVLI6sfkZ5E4 Iowa_Precincts); U.S. Census Bureau 2020 TIGER/Line VTDs where no official layer; Iowa Legislative Services Agency precincts (2016 file) for the 2020 general
Results
Certified results for Iowa Senate District 8
State Senator District 8
Iowa General Election 2024-11-05 · Nov 5, 2024| Candidate | Party | Votes | Share |
|---|---|---|---|
| Mark CostelloRepublican | Republican | 25,069 | 70.5% |
| Ryan Lee RoenfeldDemocrat | Democrat | 10,432 | 29.3% |
| Write-in | 73 | 0.2% |
Certified — Iowa county canvass results as published by the Iowa Secretary of State (Clarity ENR final county uploads; county totals reconcile exactly to the State Board of Canvassers canvass summary) · Iowa Secretary of State — Election Night Reporting / Precinct Results by County
State Senator District 8
Iowa General Election 2020-11-03 · Nov 3, 2020| Candidate | Party | Votes | Share |
|---|---|---|---|
| Dan DawsonRepublican | Republican | 12,391 | 52.1% |
| Steve GormanDemocrat | Democrat | 11,344 | 47.7% |
| Write-in | 31 | 0.1% |
Certified — Iowa county canvass results as published by the Iowa Secretary of State (Clarity ENR final county uploads; county totals reconcile exactly to the State Board of Canvassers canvass summary) · Iowa Secretary of State — Election Night Reporting / Precinct Results by County
Not on file for Mark yet: Key Votes, Their Money, Advertising, In Their Words, In the News, Reach Them, Polls, The Paper Trail. Coverage varies by state and office.
File read Sep 25, 2026. Each item names its source. Record ID p_fmd1cghww.
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