The remains of a human body were found in the Sandringham Estate, the holiday retreat of Britain's royal family, on New Year's Day, according to a posting on the Norfolk Constabulary website.
The remains were found by a morning walker in an area of woodland at Anmer, near King's Lynn in Norfolk.
The Queen and royal family were told.
"The remains were found by a member of the public. The area has been sealed off and a detailed search is being carried out," said Norfolk police.
The age and sex of the remains have not been determined and Buckingham Palace has declined to comment.
Anmer is three miles (5 kilometres) from Sandringham Palace, the private residence of British royalty since 1862. The 20,000-acre (8,000-hectare) estate includes gardens, mudflats, woods, and farmland. More than 100 employees work at the estate.
Queen Victoria had bought the estate for the then Prince of Wales, who later went on to become King Edward VII. The mansion has nearly 300 rooms.