Ald Mirathi is a shrine to the Daedra Prince Mehrunes Dagon, on the shores of Lake Boethiah.
It stands on the west bank of the lake and is a short distance south of Hla Bulor.
The treasure is typical for a daedric shrine, including gold, scrolls, books and potions. An Orcish helm sits on a bedroll in a corner of the main chamber next to a wizard's chest. Among the offerings to Dagon on the altar before his statue are two diamonds and a daedra heart, but be careful as the latter is cursed and will summon a dremora lord.