Which states have the highest share of registered Republicans in 2025?

1. What the registration numbers actually say — who’s highest by share

State voter‑registration reporting that includes party shows Wyoming with the highest percentage of registered Republicans in 2025: USAFacts lists Wyoming at roughly 77.2% of registered voters identified as Republican ^[1]. Multiple secondary summaries and local fact pieces echo that Wyoming is the top state by share, sometimes reporting it “over 80%” depending on the cut and date of the snapshot ^{[3] [2]}. Available sources do not provide a single consolidated ranked table in this packet, but USAFacts’ August 2025 compilation is the clearest statement that Wyoming registers the largest Republican share ^[1].

2. Small states and rural regions dominate the “most Republican” rankings

The states with the highest Republican shares tend to be low‑population, rural states in the Mountain West and Appalachia. World Population Review and similar rankings put West Virginia, Idaho and other interior states high on Republican measures such as CPVI and party registration; West Virginia is repeatedly listed among the most Republican states ^[2]. Wikipedia’s state‑by‑state summary also identifies a plurality of Republicans in states including West Virginia, Kansas and others — underscoring that these “most Republican” labels are geographically concentrated outside large metropolitan coastal centers ^[4].

3. Big states have the largest Republican raw totals but not the highest shares

California and Florida contain the largest numbers of registered Republicans in absolute terms — USAFacts reports California with about 5.8 million registered Republicans and Florida with about 5.5 million — yet those large raw totals translate into much smaller shares in California (25.2%) than in Wyoming ^[1]. Ballotpedia and other compilers stress this distinction: the numerical lead in large states doesn’t equal a top ranking by percentage of registrants ^[5].

4. Methodological caveats: not every state reports party on registration

Any ranking based on “registered Republicans” is limited by which states publish party on registration. USAFacts, Ballotpedia and other aggregators emphasize that national totals omit states that do not record party on registration; USAFacts’ national Republican and Democrat counts are drawn only from jurisdictions that report party affiliation ^{[1] [5]}. That gap can change national tallies and complicates direct state‑to‑state comparisons if one source includes slightly different sets of states ^{[1] [5]}.

5. Different measures give different “most Republican” lists

“Most Republican” can mean (a) highest share of registered voters who are Republican, (b) most registered Republicans in raw numbers, or (c) strongest partisan voting index (CPVI). World Population Review uses CPVI and election results to rank “most Republican” states, producing a different ordering (e.g., West Virginia high on CPVI) than registration‑share lists like USAFacts ^{[2] [1]}. Carefully note which metric a headline cites before accepting a direct comparison ^{[2] [1]}.

6. Trends and context: registrations are shifting in places but data varies by locale

Reporting from Ballotpedia and state outlets shows that registration balances change over time; Ballotpedia counts 11 states where Republicans are the largest registration group among reporting states, and notes Democrats lead in 11 states and independents in 10 — demonstrating that the roster of “Republican‑majority registration” states is not fixed ^[5]. Connecticut local reporting likewise shows Republican registration rising in some urban areas between 2021 and 2025 even where Democrats remain dominant statewide, signaling local shifts beneath state totals ^[6].

7. What reporters and analysts should watch next

Verify which metric a source uses (share vs. raw numbers vs. CPVI), confirm whether a state reports party on registration, and use the most recent state election office data when possible — Florida’s official Division of Elections posts monthly totals, for example, that can differ from national aggregators’ snapshots ^{[7] [1]}. Aggregators differ in scope and cut‑off dates; always cite the dataset and date when naming “most Republican” states ^{[1] [5]}.

Limitations: available sources here do not include a single, complete ranked list of all 50 states’ 2025 Republican registration shares in one table; the strongest direct claim in these materials is USAFacts’ statement that Wyoming has the highest percentage of registered Republicans at about 77.2% ^[1].