Tadg mac Cathail (died 956) was King of Connacht.
References
Leabhar na nGenealach, Dublin, 2004–2005 Annals of the Four Masters, ed. John O'Donovan, Dublin, 1856 Annals of Lough Ce, ed. W.M. Hennessey, London, 1871. Irish Kings and High Kings, Francis John Byrne, 3rd revised edition, Dublin: Four Courts Press, 2001. "Ua Ruairc", in Seán Duffy (ed.), Medieval Ireland: An Encyclopedia. Routledge. 2005. pp.