Brooklyn Gittins telephoned her grandmother late Thursday night from a Wal-Mart store in South Jordan, Unified Police spokesman Lt. Justin Hoyal said. The woman then contacted police and officers located the child.
"Brooklyn was not injured and is fine," Hoyal said. "She was still wearing the grey T-shirt and black pajama pants. She did not have on shoes, a coat."
Hoyal said authorities suspect that she was harbored by someone and police are trying to find out who.
She disappeared Tuesday evening wearing only pajamas and shirt. A major snowstorm Thursday prompted some 1,000 volunteers to join police in searching 17 square miles in the area near Gittins' home in Herriman, a Salt Lake City suburb about 18 miles southwest of downtown.
A key concern had been the frigid winter weather. "Investigators believed she could have been a victim of the elements; it's been extremely cold," he said.
The storm was expected to dump as much as 7 inches of snow and bring freezing temperatures.
Police have been interviewing the child, trying to determine where she was.
There were no signs of forced entry at the Herriman home where Brooklyn was last seen at bedtime Tuesday.
"We believe she left her home through her bedroom window and was picked up and harbored by a person or persons," Hoyal told The Associated Press in an interview.
Salt Lake County Sheriff Jim Winder said Thursday before she was found that the circumstances surrounding the case concerned authorities, especially because it appeared her departure was unplanned.
Gittins' grandfather Craig Hiller made a plea at the news conference for her to come back. He said she's a typical teenage girl who is very outgoing in some cases and very subdued in others.
The first time she ran away, she came back a short while later, Hiller said.
"This was a successful investigation and we appreciate all the efforts by the community, public safety personnel, and the media in response to Brooklyn's disappearance," Hoyal said.