Democrat leads narrowly in race to keep his job with 46 candidates trying to replace him
The GOP has not won a statewide election in California, one of 20 states with a mechanism to recall a sitting governor, since 2006.
The last time the move was successful was in 2003, when Democratic governor Gray Davis was recalled and replaced by Hollywood star Arnold Schwarzenegger, who ran as a Republican.
Voters will be asked two questions on the 2021 ballot.
The first one is should Mr Newsom be removed, yes or no? And the second question is a list of replacements that voters can choose from.
Voters do not have to answer both questions, and Mr Newsom has encouraged his supporters to vote “no” and to not pick any of the candidates running to take his job.
If a majority of voters agree that Mr Newsom should be recalled then the candidate on the list with the most votes will replace him.
Mail-in ballots must be postmarked by 14 September and returned in the envelope, which does not require a stamp.
Voters can also return their ballot in secure drop boxes across the state by 8pm on 14 September and there is also the option to vote in person early or on the day.
If the recall has been successful, the California Secretary of State will certify the election result 38 days after the election and a new governor will be sworn in.
There are 46 candidates listed on the ballot, including reality TV star Caitlyn Jenner, businessman John Cox who has campaigned with a 1,000lb Kodiak bear, and West Hollywood personality Angelyne.
Leading Republican candidates include Conservative talk show host Larry Elder, who during the campaign was accused by a former girlfriend of brandishing a gun and domestic abuse.
Prosecutors have declined to pursue a criminal complaint against him.
Mr Newsom’s campaign has portrayed the recall effort as an attempted Trump takeover of the state, where the one-term president lost to Joe Biden by 5m votes last November.
But with just over two weeks left until election day and with millions of ballots already having been counted, it is still a surprisingly tight race.
Mr Newsom won election in 2018 by 24 points, and Mr Biden took the state by 29 points.
But a FiveThirtyEight average of election polls last Thursday showed that 50.6 per cent of voters want to keep Mr Newsom in office, while 46.3 per cent want him recalled.
But if Mr Newsom is removed from office, it is Larry Elder that leads as his replacement on 21 per cent, according to FiveThirtyEight.