Ivy Marie Leinen was reported missing at 4 p.m. Sunday. She was last seen east of the Poplar bridge, about seven miles east of Poplar. Officials say the girl went for a walk with four of the family's dogs Sunday afternoon, but the dogs returned to the residence without her.

Searchers tracked the girl to an island in the river and part way across the ice-covered river to an open area. The tracks did not return from that spot, leading searchers to believe the girl may have fallen into the river, officials said Monday.

Ivy is 5 feet, 7 inches tall, 185 pounds with short brown hair and brown eyes. She was last seen wearing a knee-length pink dress, white and blue running shoes and white socks. Anyone with information is asked to call Sheriff Brad Baisch at 406-443-2919.