Family name Ниалл (Niall 
, Ниалл 
) , in all the world, is a rare last name. The cognomen Ниалл is characteristic of Andorra, where it is quite a rare surname, Ireland, and Australia, where it is a rare surname. Not in comparison with a country's population, the name is most common in Australia, Ireland, and Hungary. Predominantly, Ниалл is the forename as well as the last name.