The pair, whose engagement was confirmed last month, is to take place on Saturday May 19 at St George’s Chapel, Windsor Castle.
American actress Ms Markle is set to appear at church with the Windsors at Sandringham on Christmas Day.
The wedding falls on the day of the 2018 FA Cup Final.
As President of the Football Association, Harry’s older brother the Duke of Cambridge usually attends the high-profile match and presents the trophy.
But this year, William, who is tipped to be Harry’s best man, looks likely to be otherwise engaged with wedding duties.
Harry and Ms Markle have gone against tradition by choosing a Saturday.
Royal weddings usually take place on a weekday. The Duke and Duchess of Cambridge wed on a Friday and the Queen on a Thursday.
But Harry and his fiancee’s choice avoids the issue of whether the royal celebration should be a bank holiday.
May 19 is also the day in 1536 when Anne Boleyn, second wife of Henry VIII and mother of Queen Elizabeth I, was executed on Tower Green for alleged adultery.
The May wedding will also have been picked to give Kate time to recover after the birth of her third child, which is due in April.
Palace aides have already said that the prince and Ms Markle’s wedding will “reflect their characters and personalities” and be a moment of “fun and joy”.
They will say ‘’I do’’ in the historic surrounds of the Castle’s 15th century St George’s Chapel.
Ms Markle, who is to become a British citizen, is being both baptised and confirmed ahead of the religious ceremony.
The royal family are paying for the wedding, including the church service, the music, the flowers and the reception.
But the security costs for the high-profile event are falling to the taxpayer.
The Queen will be there, as will the rest of the royal family, along with Ms Markle’s parents Thomas Markle and Doria Ragland.
Prince George and Princess Charlotte look set take on the roles of pageboy and bridesmaid.
Harry proposed to Suits star Ms Markle during a cosy night in over a roast chicken dinner after a 16-month whirlwind romance.
In his engagement interview he told of how ‘’the stars were aligned’’ when he fell for his future wife, whom he met on a blind date.