Kelly Honey, who attended the ceremony, along with several other great-grandchildren and great-great-grandchildren, said: "I think it is so touching. I think it's wonderful."
The ceremony and plaque dedication is the first of many that will eventually recognize all 24 city police officers killed in the line of duty.
Speakers at the ceremony included Mayor Ralph Becker, police Chief Chris Burbank and Salt Lake Tribune columnist and former police officer Robert Kirby.
Becker said it an honor to recognized the fallen officers.
"There aren't many jobs where someone goes to work every day and they don't know if they are going to come home," he said.
Kirby recounted how William Lee, 24, who had jumped parole a month earlier in California, robbed the State Cafe at gunpoint at around 11:30 p.m. on Feb. 16, 1924.
As Lee fled the restaurant to join his fiancée, 25-year-old Beatrice Hunter, the owner of the cafe fired a shot at them, attracting the attention of police.
Honey soon spotted the man and followed him to Main Street, while Huntsman went a different direction. A gun battle erupted. The robber shot and killed 26-year-old Huntsman and wounded Honey, 24, who died hours later.
Lee, who also was wounded, dragged himself and Hunter into a doorway, where he shot her in the face and then killed himself.
"It was possibly the bloodiest day in [Salt Lake City] police history," Kirby said.
Hunter, who survived, was charged with murder. But she claimed to know nothing of the robbery beforehand and was never tried.
Tim Jackson, another of Brigham Honey's grandchildren, helped unveil the plaque and said he would like to see more memorials for officers in Salt Lake City and other cities.
"I think it is wonderful," he said. "I think it's great."
Gary M. Huntsman, a relative of officer William Huntsman and of former Gov. Jon Huntsman Jr., said the plaque was a great tribute.
"It's truly an honor to be here and share this moment," he said.