Family name Borghildur (Borghildur 
) , in all the world, is an extremely rare surname. Much more frequently, Borghildur is the forename as well as the last name.
Josuadottir, Jónsdóttir, Jósúadóttir, Magnúsdóttir, Sturludóttir, Rúnarsdóttir, Eiríksdóttir, Hjartardottir, Guðmundsdóttir, Erlingsdottir, Kristjánsdóttir, Sigurdardottir, and Kristjansdottir