The 2018 Orange County Board of Supervisors elections were held on June 5, 2018, and November 6, 2018. Three of the five seats of the Orange County, California Board of Supervisors were up for election.
County elections in California are officially nonpartisan. A two-round system was used for the election, starting with the first round in June, followed by a runoff in November between the top two candidates in each district. Runoffs are only held if no candidate receives a majority in each district.
Seats where the margin of victory was under 5%:
District 2 consists of coastal Orange County, including Huntington Beach, Costa Mesa, Cypress, La Palma, Los Alamitos, Newport Beach, Seal Beach, most of Fountain Valley, and neighborhoods in southern Buena Park.
District 4 consists of inland northwestern Orange County, taking in Fullerton, La Habra, Placentia, Brea, western Anaheim, and most of Buena Park. Incumbent Shawn Nelson retired to run for California's 39th congressional district.
District 5 encompasses southern Orange County, including Aliso Viejo, Laguna Hills, Laguna Niguel, Laguna Woods, Lake Forest, Mission Viejo, Rancho Santa Margarita, San Juan Capistrano, Laguna Beach, San Clemente, and Dana Point.
Official campaign websites of second district candidates
Official campaign websites of fourth district candidates
Official campaign websites of fifth district candidates