Attorney General Democratic candidate Kamala Harris has a less-than-one percentage point lead over Republican candidate Steve Cooley with 99 percent of precincts in.
Harris has 46 percent of the vote while Cooley has 45.7 percent. The margin is 22,299 votes with as many as a million late mail-in ballots yet to be counted.
The cliffhanger race is the California GOP's last hope of winning a statewide office in an election that resulted in stinging defeat for Republican candidates. Cooley is the Los Angeles County District Attorney and Harris is San Francisco's District Attorney.
Nicole Winger, spokeswoman for the Secretary of State's office, said the office asks counties to voluntarily provide estimates of unprocessed ballots by late Thursday after an election. By law, though, they have 28 days to report results.
"It would be safe to say there are at least several hundred thousand ballots still to be counted," Winger said. She said that after the 2008 general election that there were still 747,000 uncounted ballots the day after Tuesday balloting.
This post was updated with comments from Nicole Winger at 1:11 p.m.