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Which states will have open Senate seats due to retirements in 2026?
Executive summary
As of the latest compiled reporting, at least seven U.S. senators have announced they will not seek reelection in 2026 — four Democrats and three Republicans — creating open seats in states including Michigan, New Hampshire, Minnesota, North Carolina and Iowa; additional open contests arise from special elections in Florida and Ohio tied to 2025 resignations (specials occur concurrently with 2026) [1] [2]. Major outlets and trackers (Ballotpedia, NPR, Reuters, Roll Call and forecasting sites) list retirements by name (e.g., Gary Peters, Jeanne Shaheen, Tina Smith, Thom Tillis, Joni Ernst) and note that these departures reshape the competitive map for control of the Senate [3] [1] [4] [5] [6].
1. Which states will have open Senate seats because of retirements — the topline
Multiple trackers and news outlets show seven incumbent senators are retiring and therefore creating open-seat contests: Democratic retirements reported include Michigan (Sen. Gary Peters), New Hampshire (Sen. Jeanne Shaheen) and Minnesota (Sen. Tina Smith); Republican retirements include North Carolina (Sen. Thom Tillis) and Iowa (Sen. Joni Ernst); other outlets count retirements that collectively add to seven seats not defended by incumbents in 2026 [3] [1] [5]. Ballotpedia explicitly states “Seven U.S. Senate incumbents—four Democrats and three Republicans—are retiring” and offers state-by-state tracking [1].
2. Why those open seats matter to control of the Senate
Analysts and forecasting sites stress that retirements amplify competitiveness because incumbency advantage disappears; Democrats need a net gain of four seats to win the majority in 2027, and the loss of incumbent defenders in swing or competitive states (e.g., Michigan, New Hampshire, Minnesota) makes that task harder — or conversely, creates pickup chances for the opposing party — depending on the state [4] [7] [3]. Reuters highlights North Carolina as an open seat Republicans must defend after Thom Tillis’s retirement, while other outlets emphasize Michigan as an open target after Gary Peters’s announcement [5] [3].
3. Special elections complicate the map: Florida and Ohio
In addition to regular retirements, two special Senate elections will be held concurrently with the 2026 cycle because senators resigned in 2025 (Florida’s Marco Rubio and Ohio’s J.D. Vance); those seats will be on the 2026 ballot as special elections and could be filled permanently that November, effectively increasing the number of competitive contests that cycle [2]. Forecasts typically treat these specials as part of the 35-seat slate up in 2026, which reshapes the path to a majority [7].
4. How major outlets and trackers differ in emphasis
Ballotpedia gives a concise count (seven retirements) and maintains a state-by-state candidate table [1]. NPR frames the 2026 cycle as having a record level of retirements overall (10 senators and dozens of House members), noting that 20 members are retiring from public office rather than running for other posts [6]. Sabato’s Crystal Ball and other forecasters focus on ratings and how open seats change the partisan math for the chamber [4] [7]. Reuters highlights a handful of races to watch and names specific retirements that turn seats into battlegrounds [5].
5. Names to watch (reported retirements tied to open seats)
Reporting repeatedly cites the following retirements that produce open-seat contests: Sen. Gary Peters (Michigan), Sen. Jeanne Shaheen (New Hampshire), Sen. Tina Smith (Minnesota), Sen. Thom Tillis (North Carolina), and Sen. Joni Ernst (Iowa), among others — these names appear across Roll Call, Reuters and other trackers cataloging retirements [3] [5] [1]. Ballotpedia’s summary also lists the total and provides sourcing for each announced decision [1].
6. Limitations, unanswered items and evolving nature of the map
Available sources do not provide a single, static checklist of every state with a retirement-only open seat beyond the cited retirements; trackers differ slightly on timing and whether special elections are counted with the regular slate [2] [1] [7]. Retirements and candidate announcements continue through the cycle — NPR notes retirements were still accumulating into mid‑September 2025 — so the list of open seats can change as more incumbents announce decisions or resignations occur [6]. Also, some outlets emphasize competitiveness and forecasting differences rather than enumerating every open seat [4] [7].
7. What to watch next and why it matters to readers
Watch candidate entry announcements in the named states (Michigan, New Hampshire, Minnesota, North Carolina, Iowa) and updates from Ballotpedia, Sabato’s Crystal Ball and major outlets for changes; special elections in Florida and Ohio will be on the 2026 ballot and could alter the effective number of pickups required for control [1] [2] [4]. Given the slim majority arithmetic and multiple open seats, retirements materially reshape which party has the advantage in 2026 — a point emphasized in forecasting and reporting [7] [3].
If you want, I can extract the specific retiree names and link each to the state in a simple list drawn only from these trackers, or produce a state-by-state table of all seats up in 2026 including which are open vs. held by incumbents, using the cited sources above.