That's higher than the previous record of 16.6 million registered voters in California.
And it shows in the sheer number of calls coming into the Secretary of State's help line and the loads of mail-in ballots that have already been turned in, 2.1 million so far, which is a third of the number mailed out. That's also on track to breaking records.
Despite the heavier workload, Secretary of State Debra Bowen predicts Election Day will go smoothly in this state.
"I don't foresee any meltdowns. The Brennan Center at New York University Law School has rated California as one of the five best prepared states for this election," said Debra Bowen, Calif. Secretary of State.
That's partly because California now mostly relies on paper ballots after problems with electronic voting machines.
The state has pretty much done away with touch screen voting. Each precinct is allowed to have only one, and it must have a paper trail.
That's to accommodate voters with physical challenges.
The California Democratic Party, though, has concerns about people being turned away at the ballot box.
"We're going to have 1,200 lawyers volunteering their time on Election Day on an 800 number so that people can call in and get information if they're denied access to a polling place," said Art Torres, Calif. Democratic Party Chairman.
And the California Republican Party questions whether precincts can handle the long lines expected on November 4.
"You could have some polling stations that are overwhelmed with voters who are turning out, and you have logistical-level problems," said Ron Nehring, Calif. Republican Party.
With turnout expected to be high, this Election Day will certainly test the state's system.
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