Tir Tairngire: "the Land of Promise"
Tonn Clidna: a loud surge in the Bay of Glandore
Tonn Rudraige: a huge wave in the Bay of Dundrum, in the County Cork
Tonn Tuage Inbir: "the Tuns," near the mouth of the river Bann on the north coast of Antrim
Tor Breogain: "Bregon's Tower," in Spain
Tromma: south-east of Cruachan; also the name of a river flowing into the Boyne near Slane
Tuaim Mona: Tumona, a townland in the parish of Ogulla, near Tulsk, south of Cruachan Ai, County Roscommon
Tuatha Bressi: a name for the people of Connacht
Tuatha De Danann: "the Tribes divine of Danu," the gods of the Irish Olympus