Primary Rules
How Iowa's Primary Works
Iowa uses a Closed Primary system
Closed Primary
Only voters registered with a political party can vote in that party's primary election. Independent and unaffiliated voters are excluded.
& Party Affiliation Statistics
Key voter registration statistics · Updated 2026
How many registered Democrats, Republicans, and Independents are in Iowa?
| Party | Registered Voters | % of Total |
|---|---|---|
Democratic | 561,827 | 27.52% |
Republican | 748,167 | 36.64% |
Independent/Other | 731,861 | 35.84% |
Iowa uses a Closed Primary system
How many eligible Iowa residents actually vote?
| Election | Turnout | Voted |
|---|---|---|
| 2024 General | 70.8% | 1,674,011 |
| 2022 General | 52% | 1,230,417 |
| 2020 General | 72% | 1,700,130 |
| 2024 Presidential Primary | 5.4% | 110,272 |
| 2024 State Primary | Estimated ~17% — SoS aggregate PDF blocked; no official total confirmed | — |