The prince and his US girlfriend Meghan Markle are expected to be given a set of Scottish titles following their wedding in May, and one of the suspected front-runners is earl and countess of Deloraine.
Deloraine is a territory centred around a burn of that name running down from a Selkirkshire hillside to join the Ettrick Water.
The earldom has been extinct for over 200 years, but its military links appear to make it an ideal candidate for the Queen’s grandson as he served nine years in the armed forces, as does the fact that three of its four holders have been called Henry.
McBookie.com puts Deloraine as 4-1 third favourite behind Ross, the 6-4 frontrunner, and Dumbarton at 3-1.
Wendy Bosberry-Scott, co-editor of the reference book Debrett’s Peerage and Baronetage, said: “The Scottish title Prince Harry receives is likely to be an earldom, but there are very few clues here.
“One potential candidate is Ross, but this was last held by Charles I, who was executed in 1649, so it may well be considered unlucky, but, at this point, it is merely speculation and many factors will have to be considered before a suitable title is chosen.”
In England, Harry, 33, and Meghan, 36, are expected to be known as the duke and duchess of Sussex, but the Queen also has to decide which Scottish titles to bestow on the pair.
Harry is likely to be made an earl rather than a duke, ensuring he doesn’t outrank brother William, Earl of Strathearn.
The Deloraine title was created in 1706 by Queen Anne for her cousin Henry Scott.
Other vacant earldoms for Buckingham Palace to choose from include Ormond at 7-1 and Forfar, near the late Queen Mother’s childhood home of Glamis Castle, at 8-1.
McBookie spokesman Paul Petrie said: “This might seem like a bit of royal pass-the-parcel, but actually a lot of thought and research goes into bestowing a title.
“There is history and prestige behind each one, and the Queen will be advised on what is the best fit for the couple and no doubt have her own ideas too.
“These titles are used officially when members of the royal family come to Scotland. It ensures we continue to have our own distinct identity within the United Kingdom and don’t just follow the lead from England.”
He added: “History may be pointing to Ross or Dumbarton, but the fact that the earls of Deloraine were largely military men called Henry is a remarkable coincidence, and its romantic motto – amo in Latin, meaning ‘I love’ – might just swing it if Harry and Meghan get a say in the matter.
“Then again, perhaps Forfar would be the perfect choice for a prince and his bridie.”
Other princes have their own Scottish titles, Charles being the Duke of Rothesay and Philip the Duke of Edinburgh.