The girl, identified by the Burnett County Sheriff's Office only as Renna, wandered away from her home in Danbury, Wis., at around 7 p.m. Tuesday, the Minneapolis Star Tribune reported. A search that night using a Minnesota State Patrol helicopter and dogs turned up no trace of the little girl and was called off around 3 a.m.
Danbury is a hamlet with a population of less than 200 on the St. Croix River, which forms the boundary between Minnesota and Wisconsin. Renna's family lives two or three miles from the river, the St. Paul Pioneer Press reported.
The Wisconsin Department of Natural Resources has been searching the river and the area around the Danbury Dam, the Press said.