Friday may be the last day of early voting in Maryland, but polling officials say long lines will likely mean that final early ballots will be cast after midnight, early Saturday.

As of Thursday night, 323,188 people — or about 8.75 percent of eligible voters — had voted, according to unofficial numbers from the Maryland State Board of Elections. That compares with 219,601 — or 6.33 percent of eligible voters — in 2010.

To make up for two days of early voting that were canceled last week during superstorm Sandy, Maryland Gov. Martin O’Malley (D) extended poll hours to Friday and ordered polling places to stay open until 9 p.m.

On Wednesday and Thursday, that meant long lines, too. Voters waiting at 9 p.m. -- when local sheriff’s deputies take up position at the end of the line -- didn’t get to vote until more than two hours later.

But on Friday, with lines surging as schools let out, some local elections officials were forecasting the final night would turn into an early morning.

“Maybe 12:30 am, maybe later,” said Doris Mouser, a chief elections judge at Bowie Public Library, where more than 350 people were waiting at 3 p.m.

Those near the front of a line, which snaked the length of more than two city blocks around the parking lot, said they had been waiting for more than two and a half hours. There were still 60 people ahead of them zigzagging toward a meeting room where the voting machines stood.

Keith McKenzie, 56, an electrical engineer, had taken the day off, his 16th wedding anniversary. He had not expected that voting early would take up such a chunk of it.

“This is longer than I waited in ‘08,” said McKenzie, who said he worried his wife’s patience was wearing thin. She had voted absentee and was waiting at home.

“She’s not mad, not yet. But the longer this goes ...”

John Wagner contributed to this post.