Catherine "KAY" Cotter was last seen by family on Tuesday at 6:30 a.m. at her home on Garth Road, in Eastchester.
Mrs. Cotter suffers from dementia and has been known to sometimes walk the Garth Road area.
A slight possibility exists that Mrs. Cotter took a Metro-North train from the Scarsdale Station in either direction, officials said.
The Eastchester Police Department's Detective Division is actively investigating the Mrs. Cotter's disappearance.
Anyone who may have had contact with or observed Mrs. Cotter is asked to please contact the Eastchester Police Department at (914) 961-3464.
Callers may remain anonymous.