The government building was one of just 37 polling locations across the county, far fewer than in past years, because of the county's reliance on mail-in ballots.
The waits were longer at other Salt Lake County locations. According to social-media reports, there were waits of two hours at the University of Utah's Marriott Library, Holladay City Hall, the Bingham Canyon Lions Club in Copperton and the fire station in Herriman.
An Elections Office official said lines still were going out the doors well after the 8 p.m. closing time at two locations: Murray City Hall and Salt Lake City's First Congregational Church.
Voters who visited polling places in the morning endured similar waits: Two hours at West Valley City's Hunter Library, 90 minutes at Holladay City Hall and Salt Lake City's Marmalade branch library, an hour at Murray City Hall, and an hour-plus at Cottonwood Heights City Hall.
According to preliminary figures from the Utah Lieutenant Governor's office, as of Monday afternoon, officials had processed 222,531 mail-in ballots from Salt Lake County voters 43.5 percent of the county's active registered voters. Statewide, 41.4 percent of mail-in ballots from active registered voters had been processed.
Swensen's office mailed out more than 510,000 ballots, she said, but many people "were sitting on their vote-by-mail ballots," she said.
Salt Lake County set up 17 locations for in-person early voting, but only 15,000 people used them, Swensen said.
Expecting an onslaught on Election Day, Swensen said she tried to deploy extra voting machines and poll workers at various locations. It wasn't enough to avoid the lines.
Swensen even proposed setting up "mega-voting centers" at West Valley City's Maverik Center and the South Towne Expo Center in Sandy. The plan was thwarted by a bond proposal on the Salt Lake County ballot, which required too much advance notice to add or change polling locations.
Some voters were ill-informed about mail-in voting. Ronald Shamo, a voter in West Valley City, said he didn't know about it "until my wife informed me while we were waiting in line" at Hunter Library.
Others distrusted the post office. "I wanted to know that my vote counted," said Sue Joiner, a voter in West Jordan.
Still others preferred the community feeling of voting in person. "I want to push the button," said Lisa Sewell, executive director of the Utah Arts Festival, who stood in line at the Marmalade library. "I want to be there and [have a chance to] cast my vote for the first woman president."
Problems popped up in other Utah counties. In Iron County, at the Cedar City Council chambers, the only polling location in the city of 30,000, voters endured a three-hour wait.
In Washington County, a glitch in the voting machines Tuesday morning forced many St. George to resort to paper ballots, or come back to vote later in the day. Utah election officials got the Washington County machines back online by midday, but not before Republican presidential nominee Donald J. Trump blasted an inaccurate tweet about "voting machine problems across the entire country" drawing a stern correction on Twitter from Utah Lt. Gov. Spencer Cox.
At Trolley Square, the influx of voters was good business for Coffee Connection, a coffee shop across the corridor from the polling place. The two employees working Tuesday morning had to call in the manager, Mason Yates, to lighten the load.
"We've been out of control since 7 a.m.," Yates said.
"Usually on Tuesdays, I can finish a novel," said barista Kennedy Granger.
Tribune reporters Lee Davidson and Matt Canham contributed to this report.