Joaquin Jimenez, the former Half Moon Bay mayor, is taking on incumbent Ray Mueller for San Mateo County’s District 3 supervisor seat, setting up a coast-versus-Peninsula clash that could be over in one night. The June 2 primary could decide the race outright if either candidate clears 50 percent of the vote.
District 3 stretches from Menlo Park and San Carlos out to Half Moon Bay, Pescadero and Pacifica, tying together suburban tech corridors and rural coastal towns. Jimenez is pitching himself as the unequivocal coastside voice, centering farmworker housing, local agriculture and trades training in his platform. As reported by SFGATE, he has made his long-standing community work and farmworker advocacy the backbone of his campaign.
Jimenez served on the Half Moon Bay City Council from 2020 to 2024 and became the city’s first immigrant mayor. He lost his reelection bid in November 2024 to Paul Nagengast. During his council tenure, he pushed for senior and farmworker housing projects, including a proposed development at 555 Kelly Ave, and publicly defended former Sheriff Christina Corpus during the county’s removal fight, according to The Almanac.
Mueller’s coastside record
Mueller points to Stone Pine Cove, a project of manufactured homes intended for farmworker families, as proof he has delivered for the coast. The County of San Mateo has outlined the funding and construction timeline for Stone Pine and tracked the first homes arriving on-site as the project moved toward occupancy, according to the County of San Mateo.
He also highlights a county Farmworker Housing Compliance Task Force that he helped create to inspect living conditions on the coast. Local reporting has credited Mueller with helping accelerate clean-water fixes for Pescadero schools and with supporting a pilot urgent care clinic after the coast’s only emergency room closed, coverage that has included reporting from CBS Bay Area.
Why the Corpus fight still matters
The political fallout from the removal of former Sheriff Christina Corpus is still hanging over this race. Jimenez defended Corpus, while Mueller supported the Board of Supervisors’ removal process and the appointment of an interim sheriff.
The removal proceedings, along with the judge’s findings that shaped the board’s decision, have drawn extensive scrutiny and now feed into arguments about public safety and accountability in the District 3 race. Those proceedings and their lasting political impact have been detailed by KQED and also covered by The Almanac.
What to watch on June 2
If any candidate pulls in more than 50 percent of the vote on June 2, that candidate wins the District 3 seat outright. If not, the top candidates advance to November. Local reporting and county filings show only Ray Mueller and Joaquin Jimenez on the ballot for District 3 this cycle, making the primary the likely decider of who represents both the coastside and Peninsula neighborhoods, according to SFGATE and the county candidate roster.
Beyond personalities, this is a referendum on which priorities will drive county decisions in the next term. Jimenez is betting that coastside concerns like farmworker housing, water infrastructure, and job training will resonate more than Mueller’s countywide endorsements and first-term record. Local coverage notes that the outcome will shape budget and service decisions tied to those issues, which in turn will affect coastside services and ongoing housing projects, according to the San Mateo Daily Journal.
