Massachusetts Senate
2026 forecast. Updated October 22, 2026, 09:28 UTC
40 of 40 seats are up in 2026. Democrats are forecast to hold 35 seats after November (80% range 34–35) and Republicans 5 (5–6).
Initial version. This model was tested on every state legislative election from 1994 to 2024 before publication, forecasting each as if it had not happened. It beat the simple rule “the party that holds the seat keeps it”, and its chamber seat counts were off by 2.9 seats on average (target: under 3). Districts with no two-party race last time are read from their own presidential vote, a change tested in advance that cut their average error from 17 to 13 points. It missed one of its five accuracy targets: in 2024, the calmest year on record, its ranges were wider than they needed to be (92% of results fell inside its 80% ranges; target: at most 88%). Treat the ranges as cautious. The full test record and code.
Go to a district
Shaded by the chance of a Democratic win; pale dashed chips are not up in 2026.
Districts
Chance: of a Democratic win (in a district electing several members, of Democrats winning at least half its seats). Source: where the candidate list came from.
| District | Status | Candidates | Democratic chance | Source |
|---|---|---|---|---|
| Berkshire, Hampden, Franklin and Hampshire | Decided: only a Democrat is running | Paul W. Mark (D) | official | |
| Bristol and Norfolk | Decided: only a Democrat is running | Paul Richard Feeney (D) | official | |
| Cape and Islands | Decided: only a Democrat is running | Julian Cyr (D) | official | |
| Fifth Middlesex | Decided: only a Democrat is running | Kate Lipper-Garabedian (D) | official | |
| First Bristol and Plymouth | Forecast | Michael J. Rodrigues (D), Gabriel Boomer Amaral (R) | 94% | official |
| First Essex | Decided: only a Democrat is running | Pavel M. Payano (D) | official | |
| First Essex and Middlesex | Decided: only a Republican is running | Bruce E. Tarr (R) | official | |
| First Middlesex | Forecast | Vanna Howard (D), Sam S. Meas (R) | >99% | official |
| First Plymouth and Norfolk | Decided: only a Republican is running | Patrick M. O'Connor (R) | official | |
| First Suffolk | Decided: only a Democrat is running | Nicholas P. Collins (D) | official | |
| First Worcester | Decided: only a Democrat is running | Robyn K. Kennedy (D) | official | |
| Fourth Middlesex | Decided: only a Democrat is running | Cindy F. Friedman (D) | official | |
| Hampden | Decided: only a Democrat is running | Adam Gomez (D) | official | |
| Hampden and Hampshire | Decided: only a Democrat is running | John Christopher Velis (D) | official | |
| Hampden, Hampshire and Worcester | Decided: only a Democrat is running | Jacob R. Oliveira (D) | official | |
| Hampshire, Franklin and Worcester | Decided: only a Democrat is running | Joanne M. Comerford (D) | official | |
| Middlesex and Norfolk | Decided: only a Democrat is running | Karen E. Spilka (D) | official | |
| Middlesex and Suffolk | Decided: only a Democrat is running | Sal N. DiDomenico (D) | official | |
| Middlesex and Worcester | Forecast | James Bradley Eldridge (D), Joseph Timothy Shea (R) | 98% | official |
| Norfolk and Middlesex | Decided: only a Democrat is running | Cynthia Stone Creem (D) | official | |
| Norfolk and Plymouth | Decided: only a Democrat is running | John F. Keenan (D) | official | |
| Norfolk and Suffolk | Decided: only a Democrat is running | Persis S. Yu (D) | official | |
| Norfolk, Plymouth and Bristol | Decided: only a Democrat is running | William J. Driscoll, Jr. (D) | official | |
| Norfolk, Worcester and Middlesex | Decided: only a Democrat is running | Rebecca L. Rausch (D) | official | |
| Plymouth and Barnstable | Forecast | Dylan A. Fernandes (D), Kari Della Macrae (R) | 88% | official |
| Second Bristol and Plymouth | Forecast | Mark C. Montigny (D), Robert Scott McConnell (R) | 95% | official |
| Second Essex | Decided: only a Democrat is running | Joan B. Lovely (D) | official | |
| Second Essex and Middlesex | Forecast | Barry R. Finegold (D), Theodore T. Semesnyei (R) | 97% | official |
| Second Middlesex | Decided: only a Democrat is running | Erika Uyterhoeven (D) | official | |
| Second Plymouth and Norfolk | Decided: only a Democrat is running | Michael D. Brady (D) | official | |
| Second Suffolk | Decided: only a Democrat is running | Liz Miranda (D) | official | |
| Second Worcester | Decided: only a Democrat is running | Michael O. Moore (D) | official | |
| Suffolk and Middlesex | Decided: only a Democrat is running | William N. Brownsberger (D) | official | |
| Third Bristol and Plymouth | Decided: only a Republican is running | Kelly A. Dooner (R) | official | |
| Third Essex | Decided: only a Democrat is running | Brendan Peter Crighton (D) | official | |
| Third Middlesex | Decided: only a Democrat is running | Michael J. Barrett (D) | official | |
| Third Suffolk | Decided: only a Democrat is running | Lydia Marie Edwards (D) | official | |
| Worcester and Hampden | Decided: only a Republican is running | Ryan C. Fattman (R) | official | |
| Worcester and Hampshire | Forecast | Shannon M. Teabo (D), Peter J. Durant (R) | 4% | official |
| Worcester and Middlesex | Decided: only a Democrat is running | John R. Cronin, Jr. (D) | official |