Lewis & Short

Trītīa or Trītaea, ae, f., = Τριταία, an inland town of Achaia, near the confines of Elis, now Kastritzi, Cic. Att. 6, 2, 3.
Hence, Trittenses or Trītienses, ium, m., the inhabitants of Tritia, Plin. 4, 6, 10, § 22.