The vigil was held Sunday night on Mountain View Road, near where the elk was shot, the Boulder Daily Camera reported.
"He was a beautiful animal," said Nancy Platt of Boulder. "He was hurting nobody. He didn't deserve what he got."
The elk was shot by a Boulder police officer, who has since been placed on paid leave pending an investigation. Another officer was also placed on paid leave for allegedly loading the animal's body into a pickup truck and taking it away to be processed for meat.
Vigil organizer Jim Riemersma said he wanted to give the neighborhood "a little bit of closure."
"I know a lot of us have had a lot of anger, a lot of questions, a lot of uncertainty," Riemersma said. "Tonight's a celebration, a celebration of the elk. We loved him. But I think he loved us, too, because he returned to this neighborhood."