Tyrmidra (Irish: Tír Midire, Midir's Land) is a principality in central Maltropia. It is the nth-most populous principality, home to _,___,___. Covering 43,205.27 square kilometres, it is Maltropia's second smallest principality. Its capital city is Eochaill.
Counterclockwise from the north, it is bounded by the principalities of Mag Gaethe, Escir, Fearann Ard and the Angle. It is separated from Montrose to the northeast by Na hÍsle, extensive sand flats, and the Lisdare Fjord and fronts the Bay of Bayname to the north. Tyrmidra is among Maltropia's most fertile territories, taking in the gently-sloping land between the Ardawns and the Bay of Bayname.
In the First Kingdoms era, Tyrmidra was ruled by the Uí Midire, who remained the dominant dynasty in southern Maltropia into the ninth century. Midrian royal authority was recognised as far north as Uisneach and Ivory and southward into the Ardawns, and its patrimony included the monastery of Ecriu and the Bardic College of Eochaill.