Tadg: a river in Conalle Murthemni
Taidle: near Cuib
Taltiu: Teltown, in the County Meath, on or near the Blackwater, between Navan and Kells; one of the chief places of assembly and burial of the Ulstermen
Taul Tairb: in Cualnge
Telamet: a river in Conalle Murthemni
Temair: Tara, the seat of the High King of Ireland, near Navan, in the County Meath (pronounced Tavvir)
Tethba descirt: South Teffia, a territory about and south of the river Inny, in the County Longford
Tethba tuascirt: south-east of Cruachan, in Teffia, County Longford
Tir Mor: in Murthemne
Tir na Sorcha: a fabled land, ruled over by Manannan