By Loretta Kalb, Sacramento Bee

The polls will open at 7am Tuesday, but this presidential election already is notable for the volume of vote-by-mail ballots flowing into county offices and for the large number of registered voters.

With polls staying open until 8pm, election officials predict a healthy turnout in the region.

Placer County is estimating a turnout of registered voters in the 80 percent range. In El Dorado County, the hope is for close to 85 percent. In Yolo County, about 78 percent is projected.

Sacramento County as of Friday had not projected turnout. But in the last presidential election, turnout was 79 percent.

Whatever the expectation, most of those voting won’t show up at polling places.

Most registered voters in the four-county area have shown they prefer voting by mail. And thousands of the ballots have already been returned to their respective counties’ elections offices.

In all, more than 1.1 million people are registered to vote in Sacramento, Placer, El Dorado and Yolo counties, say election officials.

The breakdown: A record 699,000 voters are registered in Sacramento County; another 208,600 are registered in Placer County; 110,700 in El Dorado County; and 102,000 in Yolo County.

Here’s how those counties stack up in the vote-by-mail category:

In Placer and El Dorado counties, approximately two-thirds of registered voters have requested vote-by-mail ballots.

In Yolo County, 55,000 vote-by-mail ballots were issued. And by midday Friday, more than 40 percent of those had been returned to the elections office, said Tom Stanionis, chief of staff for the Yolo County clerk-recorder.

In Sacramento County, elections offices have been “inundated with a wave of vote-by-mail ballots pouring in,” spokesman Brad Buyse said.

By midday Friday, more than 146,000 ballots had been returned by mail.

Officials say it’s too late to mail those ballots in if you want them to be counted. At this point, all vote-by-mail ballots must be dropped off at either your county election office or at any polling place on Election Day.

To be counted in this election, all the ballots must be received by 8pm Tuesday, Buyse said.

Sacramento County began processing vote-by-mail ballots on Oct. 26.

And while the final votes will take time to tally on election night, Buyse said the ballots that arrived in the elections office before Saturday should be largely tallied.

As a result, very preliminary vote-by-mail results ought to be available for viewing on the county’s website shortly after polls close at 8pm Tuesday.