It was around 6:00 p.m. Sunday when Delaware State Police received a phone call from a man in Carneys Point, New Jersey.
The man told police he had gone out on his boat with his daughter and her friends to Pea Patch Island from Delaware City, Delaware to go swimming.
While there, the man said he found the skull in the water approximately four feet from shore.
He told police he checked the area for more remains but couldn't find any. The man then brought the skull across the river to Carneys Point and then called police.
The skull was turned over to the Office of the Chief Medical Examiner for possible identification.
The M.E. said the skull was degraded and had been in the water for more than six months. The forensic testing is expected to take several months.
Meanwhile, Delaware State Police returned to the area of Pea Patch Island on Monday to search for more remains.
None were found.