The unidentified baby was found Wednesday afternoon in a wooded area, about 10 feet from the shoulder of a road, by a local resident out for a walk, KOMO-TV, Seattle, reported Thursday.
The baby was found about a mile from the Snoqualmie Casino.
The baby's umbilical cord was attached, Cindi West of the sheriff's office said. She did not specify the baby's gender.
"We're looking for someone to help us identify who this baby belonged to," West added.