The Ballot Brief
Massachusetts
Candidate profile

Thomas J. O'Brien

Democratic · Massachusetts · 2026 · Incumbent

On the ballot

Plymouth County TreasurerMassachusetts · 2026Plymouth County sample ballot
Biography

Thomas J. O'Brien has been Plymouth County Treasurer since 2006 and previously served as state representative for the 12th Plymouth District, per the county treasurer's official pages. As chairman of the Plymouth County Retirement Association he oversees fund assets for more than 9,000 members and 3,300 retirees, per the official pages. No campaign website was found as of September 6, 2026.

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Profile facts follow official election office filings and the sources cited in each biography. Roster last verified October 3, 2026. Official sources are the final word on who appears on your ballot.

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