Haliburton Highlands OPP responded to a call on Wednesday of a woman who appeared to be in distress on Loon Lake.
Officers arrived around 3 PM along with members of the Dysart et al Fire Department and Haliburton County EMS and found the woman with no vital signs.
Despite life-saving measures being taken, she was later pronounced dead at the hospital.
The 63-year-old was not named by police. Provincial Constable Michelle Scanlan says no further information will be released until the investigation is complete.