City spokeswoman Cora Scott estimated the size of the crowd, which marched with candles to remember the youngster, who was allegedly kidnapped and then murdered last week.
"There are no words to describe our community's broken heart," Mayor Pro Tem Jeff Seifried told the crowd gathered at a footbridge. "There are no words to describe our frustration. The unthinkable has happened in our community."
A suspect was arrested last week in the case, but participants in Saturday's vigil agreed not to discuss the arrest or even bring up suspect Craig Wood's name. "Tonight is about Hailey, not the crime," marcher Angel Boeddeker told the Springfield (Mo.) News-Leader.
Wood remained in jail without bond this weekend on kidnapping and murder charges.