The Peshtera Monastery of Saint Nicholas of Myra (Bulgarian: Пещерски манастир „Свети Николай Мирликийски”, Peshterski manastir „Sveti Nikolay Mirlikiyski”), also known as the Mraka Monastery (Мрачки манастир, Mrachki manastir) or Oryahov Monastery (Оряховски манастир, Oryahovski manastir) is a medieval Eastern Orthodox monastery in western Bulgaria, located in the Mraka area at the village of Peshtera, near Zemen, Pernik Province.