First-term Glens Falls Mayor Bill Collins was defeated in Tuesday's primary by Democratic challenger Diana Palmer.
Palmer, the 3rd ward common council member, declared victory about an hour after polls closed Tuesday. According to unofficial returns, Palmer defeated Collins 694 to 277.
A member of the common council since 2018, Palmer also serves on the SUNY Adirondack Board of Trustees.
Palmer's campaign has called for more transparency in the city's budgeting process and constructing a new comprehensive plan.
Collins, elected mayor in 2021, has secured the Conservative ballot line and will also appear on the independent Glens Falls Forward line in the November general election.
Collins congratulated Palmer Tuesday evening, saying he plans to "continue to get the word out about how great Glens Falls is doing."
Collins' campaign boasts the first zero-percent tax increase in more than two decades and highlights recent infrastructure achievements through American Rescue Plan Act and Downtown Revitalization Initiative funding.
In Fulton County, Republican Gloversville mayoral hopeful Gary Antonucci beat Matt Capano 304 to 207.
Antonucci has served on the city's water board for a decade.
Democratic mayor Vincent DeSantis announced earlier this year he would not be seeking reelection. There is no Democratic candidate for November's vote.