In addition to 11 formal challengers, Mayor Gavin Newsom also faces six write-in candidates, according to the Department of Elections.

Write-in candidates had until Tuesday to file candidacy papers with The City that included 20 valid nomination signatures of registered voters. There is no filing fee or other charge for write-in candidates, whose names do not appear on the ballot. The names of the write-in candidates for mayor are Rodney Hauge, Kenneth Kahn, Lea Sherman, Robert McCullough, Robert Kully and Patrick Monette-Shaw.

Additionally, Anthony Carrasco filed write-in candidacy papers to run against incumbent Sheriff Michael Hennessey. David Wong, president of the San Francisco Sheriff's Deputies Association, is also on the ballot as a candidate for sheriff.