Vicki Kirkwood, 55, of Merrillville, Indiana, was attending the Lake County Fair with her mother Tuesday afternoon when she went missing, police said.
A Silver Alert was sent out to the community on Tuesday as part of efforts to find Kirkwood. She had been receiving treatment for dementia, officials said.
Kirkwood was discovered in a pond Wednesday morning in the 900 block of Mary Ellen Drive in a residential area in Crown Point, Indiana, police said. She was later pronounced dead and identified to authorities by family members.
Crown Point police and the fire department dive team recovered the body from the pond, and they were assisted by the Indiana DNR and the Lake County Sheriff's Department.
The Lake County Forensic Science Center will conduct an autopsy on Thursday to determine the woman's cause and manner of death, officials said.
No further information about the death was immediately available.