Riddle, of Fruit Heights, is the second Republican in the race. Randy Minson of West Point, a communications consultant, announced his candidacy last month.
They are both seeking the seat to be vacated by Commissioner Alan Hansen, who is not seeking re-election.
In a news release, Riddle, 45, said she would work to ensure Davis County provides the right services at the right prices.
"Our county is experiencing enormous growth and change, and people need to feel that their county government is looking out for their interests with sufficient vision," Riddle said, according to the news release.
Riddle has served on a number of boards, including the McKay-Dee Medical Center Board, Zions Bank Advisory Board, Utah Tourism Industry Coalition Board and Davis Chamber of Commerce board.
- Kristen Moulton
