Katie A. Brown, county elections director, said her office had allocated resources to those polling sites based on the number of registered voters. But voters flocked to the precinct in exceptional numbers in the morning.
Meredith Curtis, a spokeswoman for the American Civil Liberties Union of Maryland, called the turnout "heartening" but said lines were "excessively long."
"Many people don't have much time to take away from their jobs, or they have child care issues," she said. "It's important for democracy to not place unnecessary hurdles in the way of people participating."
She said the state can celebrate a number of successes this year: better training of poll workers, fewer complaints, functioning equipment and precincts opening on time. "But the long lines are the unfortunate part of the story," she said.
In some areas, the pace of voting slowed later in the day but remained brisk.
By 3 p.m., a church polling place in Lutherville had seen 427 voters, about 58 percent of the precinct's registered voters - and 3 percent above the total number of voters in February's primary.
"It's a very important election, and it makes a difference at this date and time," said David Lovette, the chief election judge at the polling place in Carroll's-Gill's United Methodist Church. "And it's historical, from both parties."
Earlier, Shayna Foster, 26, waited in line for three hours for "an opportunity for change." The line at her precinct, Woodmoor Elementary in Gwynn Oak, traveled down a hallway, out the door and around the building.
"It really is a life-changing moment today, and people were going to make sure they were a part of it, no matter what," Foster said. "Voter turnout in Maryland is sketchy at times, but today is a perfect example of everyone doing their very best to make sure their vote was counted."
At George Washington Elementary School near M&T Bank Stadium, Susie Kincaid, 64, was the first of 150 people in line before polls opened. The school is near a proposed site for a slot machine parlor.
Kincaid, who lives in Pigtown and supports slots, mistakenly thought the polls opened at 6 a.m., and woke her friend, Helen DuBose, 58, at 4 a.m. to be prepared. Kincaid said they brought folding chairs, crossword puzzles and bottles of water.
"I've never seen lines like this," said Allison Pendell-Jones, 34, who lives in Ridgely's Delight.
