The remains of 8-year-old Gideon McKean were found about 2,000 feet from where the body of his mother, Maeve Kennedy Townsend McKean, was discovered on Monday, the Times said.
Both were last seen on Thursday getting into the canoe near a home where they were staying, owned by Townsend's mother.
Townsend, 40, is the daughter of former Maryland Lieutenant Governor Kathleen Kennedy Townsend and a granddaughter of Robert Kennedy, who was shot to death in 1969 while seeking the Democratic nomination for president.
Townsend's husband, David McKean, said in a Facebook post this week that his wife and son had gotten into the canoe just to retrieve a ball that had been kicked into the cove, but were pulled by the wind or tide into the greater Chesapeake Bay.
"About 30 minutes later they were spotted by an onlooker from land, who saw them far out from shore, and called the police. After that last sighting, they were not seen again," McKean wrote.
The capsized canoe was recovered the following day, miles from where they entered the water, McKean said, and a rescue search by the U.S. Coast Guard and local authorities was called off after 24 hours.
In August 2019, a 22-year-old granddaughter of Robert Kennedy, Saorise Kennedy Hill, was found dead at the family's compound in Hyannis Port, Massachusetts, of what medical examiners determined was an accidental drug overdose.
Robert Kennedy's older brother, President John F. Kennedy, was assassinated in 1963. The president's son, John Jr., died with his wife and sister-in-law in 1999 when the plane he was piloting crashed in the Atlantic off Martha's Vineyard, not far from Hyannis Port.