In one of the largest voter turnouts in King County’s history, 85 percent of the 1.1 million registered voters in King County are expected to cast ballots for the general election Tuesday.

The turnout, as predicted last Friday by the county elections department, would be two percentage points higher than in 2004, the last time a presidential race was held. Voter participation is highest for that and other high-profile contests, such as for governor – another one on this year’s ballot.

A county record 750,000 absentee (mail-in) ballots have been distributed. As of Thursday, 282,453 had been returned by voters, according to Sherril Huff, county elections director.

In addition to mail-in votes, which must be returned or postmarked no later than election day, the county elections department will tally votes from polling places. The latter will close at 8 p.m. Tuesday.

On election day, election workers expect to count about 100,000 absentee ballots plus all votes that are cast at 392 polling places. As many as 385,380 votes could come from the latter.

Starting Wednesday, results will be updated twice daily (3 and 11:30 p.m.) until the majority of ballots are counted. Huff estimated that 97 percent will be tallied by Nov. 11, a week after the election.

Officials said 930 of the absentee ballots that had been cast by Thursday were deposited in a dropbox at Black Diamond Library. Just under 23,000 other ballots were taken to nine similar dropboxes set up by the elections department at libraries and other public buildings around the county.

At the county elections headquarters in Renton, some voters reportedly waited in line Monday for two hours in order to cast early ballots, rather than wait to go to polling places Tuesday. Huff said they were reacting to news reports from other states of long lines of voters for early voting at polling places.

She said that shouldn’t happen on election day here, when there will be “a ballot and poll worker waiting for you.”

The polling places in King County will be staffed by a combined 5,000 election workers, Huff said. She urged polling-place voters who aren’t leaving town to vote Tuesday at their assigned polls.

Huff planned to brief the County Council Monday on the expected timeline needed to ensure accurate ballot-counting and official certification of the final results.