Family name Sionainn (Sionainn 
) , throughout the world, is an extremely rare last name. The cognomen Sionainn is habitual in Northern America, particularly the United States, where it is an extremely rare surname. More frequently, Sionainn is the forename as well as the last name.
Boyle, Hayes, Murphy, Lennon, Willis, Marcoux, Marcout, Mcateer, Karlssen, Kinghan, Mcglinchey, Mclaughlin, and Carmichael