Mirt (Elder Speech: Mirthe), is a stronghold in Gelibol, a region of Redania. There is a temple of Coram Agh Tera in the town. In the short story "A Grain of Truth", Nivellen reveals that it was at the temple in Mirt that he was cursed.
Mirthe was also originally the seat of power for the mages that was destroyed by Falka during the rebellion.