Nearly 4 million people in the Bay Area’s nine counties voted in the 2020 election, breaking voter turnout records in some.

Eight of those counties reported final results by Wednesday, with San Mateo being the last county in the Bay Area to certify results Thursday. San Mateo County reported nearly 86% turnout, with 380,193 ballots cast.

“The election went remarkably well, considering it was the largest in San Mateo County history and conducted in the face of the COVID-19 pandemic,” said Jim Irizarry, the county assistant registrar of voters.

Unofficially, 3,782,883 Bay Area residents voted in the 2020 general election, with the biggest number coming in Santa Clara County. Officials there reported receiving 863,964 votes, which accounted for nearly 85% of registered voters, according to the registrar’s office.

Alameda County’s 521 precincts cast 785,215 ballots, 75.4% of which were mail-in. Total turnout exceeded 81%.

Contra Costa County officials counted 591,143 votes, which was more than 76% turnout of registered voters.

San Francisco officials reported receiving 449,866 votes from the city’s 609 precincts, representing more than 86% of registered voters.

Sonoma County finished with 272,244 votes cast, which accounts for more than 90% of registered voters, according to the county website.

In Solano County, workers counted 209,002 votes out of a possible 258,850, which was a bit more than 80% of the registered voters. “We had a pretty smooth canvass period with no issues,” said registrar John H. Gardner.

Marin County saw slightly more than 90% turnout, with 158,103 of 175,220 voters casting ballots.

Napa County election officials counted 73,269 votes, accounting for more than 86% of registered voters, according to the county website.

“Napa County reached a record turnout of 86.62% during a health emergency,” said registrar John Tuteur. “I am pleased that 93.5% of our eligible citizens are now registered to vote.”

California’s 58 counties have 30 days from Election Day to report final results to the state, which concluded Dec. 4. The state must certify California’s elections by this Friday, Dec. 11. The Electoral College officially votes for the president on Dec. 14.