As of noon on Nov. 9, Mueller had 18,781 votes, or 64.3% to Parmer-Lohan's 10,436 votes, or 35.7% of the count.
District 3 is the largest district in San Mateo County by area, encompassing seven cities and 20 unincorporated areas. The district ranges from Pacifica south almost to Santa Cruz on the coast and inland communities including Atherton, Portola Valley, Woodside and West Menlo Park.
Mueller has said that his priorities are housing, education, infrastructure and putting a focus on the coastal towns in the district as well as inland cities. Parmer-Lohan said she was focused on mitigating the effects of drought, addressing wildfire risk and reproductive rights.
Parmer-Lohan, a member of the LGBTQ community, emphasized in her campaign the diversity she would bring to the board, which has been overwhelmingly straight, white and male throughout its history.
"I want to thank the residents of District 3 for participating in this historic election," Parmer-Lohan said. "I'm really proud of what we've accomplished."