The HANNON/HANNAN Irish Surname Project is researching members of the original Irish spelling of the clan/sept name - Ó hAnnáin or Ó hAnáin. This surname later changed into several "anglicized" spellings (Hannon, Hannan, Hannen, Hanneen, Hannin). This Irish surname belongs to two celtic groups of Ireland: Érainn (Fir Bolg/Belgae) celts who arrived in 500 BC from southern celtic Britain, as well as to the Gaels (Goidelic) celts who arrived in Ireland in 50 BC after leaving northwest Spain.

This surname project is being administered by Clann O'Hannon and the Ó hAnnáin Sept Association, for the purpose of helping our fellow Hannon/Hannans find their common ancestors. This is in conjunction with other officially registered Irish clans that belong to the Clans Of Ireland, Dublin Éire-Ireland. We invite anyone with ancestors that shared these Irish surnames to participate in the Family TreeDNA - HANNON/HANNAN Irish Surname DNA Project.