Police say the witnesses said the victim was wearing a life jacket but was left unattended when the others got out of the pool to eat on a nearby deck.
Police say someone noticed the woman floating in the pool about 10 minutes later.
Police say the woman was rushed by ambulance to a hospital. They say she was pronounced dead about 1½ hours later.
The woman's death remains under investigation.
NEW YORK AND TRI-STATE AREA NEWS