Tim Boyd, who holds the District 8 seat on the Hamilton County Commission, faces a challenge in the May 1 Republican primary from East Ridge Mayor Brent Lambert.
Lambert picked up papers for the seat today, according to the Hamilton County Election Commission website.
Three incumbent commissioners don't presently face opposition: Greg Martin in District 3; Sabrena Smedley in District 7 and Chester Bankston in District 9.
In District 1, incumbent Randy Fairbanks faces a GOP primary challenge from Steve S. Coker.
District 2 will be an open seat, since Jim Fields is not seeking re-election. Chip Baker has filed papers to run in the Republican primary and
Elizabeth Baker picked up papers Thursday to seek the seat as a Democrat.
In District 4, incumbent Democrat Warren Mackey has a primary challenge from Kelvin Scott; the winner will face Chris Dahl, an Independent, in the August general election.
District 5 features a three-way Democratic primary between incumbent Greg Beck and challengers Katherlyn Geter and Isiah Hester.
Joe Graham has no GOP primary opposition in District 6 but faces a general election contest with David Sharpe.
The filing deadline is Feb. 15.