Sen. Bernie Sanders led in nearly half of Orange County’s precincts.

Voters with no party preference swung the vote-by-mail turnout strongly in favor of Democrats.

And, despite a new 11-day election window and a heavy emphasis on mail-in ballots, seven out of 10 in-person voters waited till the last day, March 3, to walk into a vote center to cast their ballots.

These are a few of the local voting facts emerging as the Orange County Registrar of Voters counts the last of the ballots from the primary election.

While final numbers are expected to be certified in April, an analysis of the preliminary totals offers insight into everything from how local turnout compared to previous cycles, to which parts of the county are most supportive of which presidential contenders seven months before the general election.

Using the map below: Tap or hover over a precinct to see how people there voted. Click or tap a candidate’s name or precinct to highlight where they lead. (Some candidates lead only in one precinct.) Click or tap the same name or precinct again to reset the map colors. Select the magnifying glass icon to search for a city.

Democratic vote for president

In the 10 days since the California primary, the race to be the Democratic Party nominee for president shifted dramatically, with former Vice President Joe Biden taking a solid and potentially permanent lead over Sanders.

But that doesn’t change the fact that on March 3, Democrats in California preferred Sanders over Biden by about 34% to 28%. In Orange County, Sanders was even more popular; as of Friday, March 13, Sanders won 136,441 votes, about 36%, to Biden’s 105,098, or 28%.

See Orange County’s latest election results

The Vermont senator led in 48% of the county’s 1,703 precincts. And in some of the county’s bluest communities — dozens of precincts around Santa Ana, Anaheim and Buena Park — Sanders got more than half the total vote.

Biden led in about 30% of all O.C. precincts, largely in more affluent areas of Yorba Linda, Anaheim Hills, Newport Beach and coastal cities in South County.

The only other candidates who led in more than one precinct were Michael Bloomberg, who leads in 17 precincts, including Seal Beach senior community of Leisure World and the Newport Beach precinct that includes Fashion Island, and Massachusetts Sen. Elizabeth Warren, who leads in six.

Precinct returns also revealed a Democratic schism at UC Irvine: In a precinct that includes a lot of student housing, Sanders won 83% of the vote; in another precinct that includes faculty housing, the winner was Warren, a former law school professor.

The data also shows that for this primary, at least, Democratic candidates got some support from voters who aren’t Democrats.

That was possible because of different rules set by the state’s two biggest political parties. While the California GOP doesn’t let non-GOP voters cast primary ballots, believing their nominee should be determined by party voters only, the California Democratic Party allows independent voters to request a Democrat ballot in the primary.

In Orange County, for the March 3 primary, about 16% of voters who are registered as no party preference did just that, requesting Democratic ballots and casting nearly 65,000 mail-in votes for Democratic candidates.

No GOP mystery

With a presumptive presidential nominee on the ballot — President Donald Trump — GOP voters had less motivation than Democrats to turn out for the primary. And, predictably, on the GOP side Trump was the big winner.

But voting data shows that his support was not absolute.

Trump won about 93% of the GOP votes that named a presidential nominee, while former Massachusetts Gov. Bill Weld was second, with 2.5%. Trump won virtually every precinct and found Republican support from all parts of the county, according to election data.

Still, a non-trivial share of local GOP voters didn’t pick Trump to be their party’s nominee.

In all, 14% of Republican ballots were cast for somebody other than Trump — or for nobody at all. Data shows that GOP voters in Irvine and Laguna Beach were most likely to leave the presidential slot blank, or to choose a non-Trump candidate, while their party brethren in Yorba Linda were least likely to do so.

How we cast ballots

This month’s primary marked the first local election in which ballots were mailed to every one of the county’s 1.64 million registered voters. It also was the first to be conducted in which vote centers were open for 11 days and unmanned drop boxes — 110 spread throughout the county — were widely used as ballot collection hubs.

County election officials have said the new system is intended to make voting easier and turnout bigger.

It definitely changed the way voters cast their ballots.

Preliminary data shows more than 75% of the votes cast for the primary — more than 611,000 — were mail-in ballots, either sent through the Postal Service, dropped off at a vote center, or slipped into a drop box. In the 2018 primary, mail-in ballots accounted for 64% of all the votes cast in Orange County.

But the extended voting window — 11 days in many parts of the county and no less than four days everywhere — didn’t result in a lot of early, in-person voting. Of the roughly 191,000 people who voted in person, seven in 10 did so on Election Day.

The late walk-up vote might’ve been a result of the unsettled presidential field on the Democratic side. Several candidates dropped out in the days before Super Tuesday, and some voters said they waited so they wouldn’t “waste” a vote by supporting someone who was no longer running.

That theory is supported by the fact that roughly a third of vote-by-mail ballots were received on election day via the Postal Service, vote centers or drop boxes, even though ballots had been sent out a month earlier.

A look at voter turnout

Whether it was the new voting system, 2020-era politics or simply high interest, voter turnout on March 3 was strong for a primary election.

Data shows about 49% of registered voters cast ballots for the March 3 election. That turnout matches a prediction made by Orange County Registrar of Voters Neal Kelley when vote counting began. It’s also in line with the most recent presidential primary, 2016, and the 48.7% that turned out for the 2008 primary. (In the last primary election with an incumbent president on the ballot, 2012, turnout in Orange County was only 27%.)

Voter turnout in Orange County hasn’t yet been broken down by party, but using the presidential vote as of Friday, March 13, as a gauge, Democratic candidates for president had received 374,861 votes while GOP candidates received 293,532.

The Registrar will start auditing ballots Monday and continue through next week, according to Kelley. That includes locating and reviewing damaged ballots that did not scan on the first pass, which Kelley described as a “painstaking process.”

Certified election results are due by April 3.