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Which U.S. senators' terms expire in January 2027 (seats up in 2026)?
Executive Summary
A clear, consistent fact emerges across the materials: the U.S. Senate Class II seats — the senators whose six-year terms began with the 117th Congress on January 3, 2021 — expire on January 3, 2027, and those seats are the ones contested in the November 2026 elections (seats “up in 2026”) [1] [2]. Multiple lists and election trackers published between 2023 and November 2025 identify this same group of seats, although individual documents vary in named senators, emphasize different high-profile incumbents, and note two special elections tied to earlier resignations that will also be on the 2026 ballot [3] [4] [5].
1. Who’s claiming which senators are up — consistent core facts, different presentations
The core constitutional and calendrical claim is uniform: Class II Senate terms end January 3, 2027, so those seats are up in November 2026. Official Senate materials and class-focused lists published in 2023 and updated materials in 2025 present overlapping rosters of senators whose seats fall into Class II [1] [2]. Where the sources diverge is in presentation and emphasis: a Senate.gov-style roster explicitly lists dozens of names including high-profile Democrats and Republicans such as Cory Booker, Christopher Coons, Richard Durbin, Shelley Moore Capito, Bill Cassidy, Susan Collins, Mitch McConnell and Lindsey Graham [1]. Other outlets provide interactive maps, vulnerability rankings, or state-level summaries rather than a simple roster, which can make direct comparisons harder without cross-referencing multiple lists [5] [6].
2. Names that appear repeatedly — who to expect on the 2026 ballot
Multiple sources that enumerate Class II senators repeat a similar core set of incumbents who were elected or seated in 2020 and thus face the 2026 cycle; these include both entrenched figures and competitive incumbents. Senators named across documents include Cory Booker, Christopher Coons, Richard Durbin, Bill Cassidy, Susan Collins, Mitch McConnell, Tina Smith, Gary Peters, Jeanne Shaheen, Jon Ossoff, John Cornyn, and Edward Markey, among others [1] [6]. The apparent roster totals roughly 33 regular Class II seats, with the composition split across parties; some sources quantify the partisan breakdown and highlight which seats are considered vulnerable based on state-level dynamics and retirements [2] [5]. Readers should note that a few seats may have changed hands via appointment or special election since 2020, and such changes are flagged in more recent trackers.
3. Where sources spotlight volatility — retirements, vulnerabilities, and retirements that matter
Recent journalism and election analysis emphasize that the 2026 map includes several vulnerable or open seats that could affect Senate control, and they call out incumbents who have announced retirements or face tough prospects. A November 2025 vulnerability piece singles out senators in competitive states — citing Jon Ossoff (GA), Susan Collins (ME), John Cornyn (TX), Bill Cassidy (LA), Edward Markey (MA), Gary Peters (MI), Jeanne Shaheen (NH), Tina Smith (MN) — and reports on announced retirements and primary pressures shaping the contest [6]. Those analyses combine the Class II roster with local political trends; the result is a fluid picture where a static list of names is necessary but not sufficient for assessing 2026 dynamics. Election trackers complement roster lists by showing partisan math and individual seat competitiveness [5].
4. Special elections and the technical mechanics that complicate the roster
The 2026 ballot will include regular Class II races plus at least two special elections stemming from midterm resignations: one in Ohio and one in Florida to fill the remainder of terms vacated in 2025, which are scheduled for the same November 3, 2026, general date [3]. These special contests can produce overlapping entries on “who’s up” lists because a state may have both a regular six-year Class II race and a shorter special-term election for the same physical Senate seat depending on timing and appointments. Sources that strictly list Class II senators (the constitutional class) may not emphasize these special contests, whereas election trackers and November 2025 reporting include them as part of the practical 2026 map [2] [3]. That distinction explains apparent discrepancies among documents.
5. Bottom line and where to verify the current roster and changes
The established, verifiable fact is that Class II senators’ terms expire January 3, 2027, making their seats up in 2026, and most public rosters and election trackers concur on the core list of incumbents affected [1] [2]. For the most current and authoritative roster, consult an updated Senate roster or reputable election trackers that incorporate 2023–2025 appointments, resignations, and special-election scheduling; cross-reference Senate-class lists with 2025 reporting on retirements and special elections to capture seat-level changes [4] [5] [3]. This combined approach reconciles the constitutional class framework with the practical realities cited in recent coverage.