The Ongiin Khiid monastery sits at the foot of Saikhan Ovoo mountain, near the village of Saikhan Ovoo in the Dundgovi region.

This monastery was among Mongolia's largest and most revered before its destruction in 1939 by communist authorities.

Founded in 1660, it comprises two sites—one north and one south of the Ongi River. Khutagt, to the south, is the oldest. It once housed various administrative buildings and eleven temples. Barlim, to the north, was built during the 18th century and contained 17 temples, one of which was the largest in all of Mongolia. Four Buddhist universities were also based within the monastery complex. At its height, the monastery could accommodate up to 1,000 monks simultaneously.

During the monastery's complete destruction in 1939, under the direction of Khorloogiin Choibalsan, 200 monks were killed, and many survivors were imprisoned or forcibly conscripted into the communist military. Other monks managed to escape and became herders or laborers.

The river's water was diverted to supply local government-owned mines. The resulting depletion of the river led to the departure of the local population, and the monastery seemed destined for oblivion. However, following the fall of communist rule in 1990, three monks who had begun their Buddhist education at Ongiin Khiid sixty years earlier decided to return. Working slowly and steadily, these monks laid new foundations over the ancient ruins to restore Ongiin Khiid and revive Buddhism in Mongolia. Today, one temple has been completely rebuilt and two small museums have been established in gers. These display artifacts, traditional religious objects, and architectural elements from the original monastery.

Ongiin Khiid is also home to a cold spring, Bar Khamba, renowned for its healing properties, particularly in treating internal ailments often related to the digestive system. Following tradition, this water is believed to be effective only when drunk before sunrise.