By PA Reporter
Prince Harry becomes the first Baron of Kilkeel, as this has never previously been granted as a royal title.
Kilkeel is the capital of the ancient Kingdom of Mourne, and lies on the coast of County Down, below the Mourne mountains.
It is home to Northern Ireland's largest fishing fleet.
There has been a settlement in Kilkeel since ancient times.
Buckingham Palace said that all Baronies have a Nomen Dignitatis and a territorial designation. The title therefore is Kilkeel and the territorial designation is of Kilkeel in the County of Down.
Sir Jeffrey Donaldson, Democratic Unionist Party MP, welcomed the news on Twitter saying: "Thrilled that Prince Harry is to become Baron Kilkeel on his wedding day. The folk in my native Mourne will be over the moon. A truly historic day for Kilkeel."
Samuel Hamilton, owner of the Kilmorey Arms Hotel, Kilkeel, said: "I think that it is fantastic news. I can't believe it.
"The Queen has visited Kilkeel in the past and Charles and Camilla were here not so long ago.
"We hope now he has been made the Baron of Kilkeel that he will be visiting us in the near future.
"The Baron and Baroness are most welcome."
Woman in critical condition after she's struck by car in Belfast
Man dies following road accident in County Fermanagh
Executive will ‘have to deal’ with compensation costs from PSNI data breach
Man remanded in custody charged in connection with mosque burning plot
Woman charged over breaches at abortion safe access zone