West Baray, Ancient reservoir in Siem Reap, Cambodia.

West Baray is a rectangular reservoir at Angkor, oriented east–west just west of Angkor Thom, measuring about 7.8 by 2.1 kilometres and holding up to 53 million cubic metres. Its water is held by earthen dikes 11.9 metres high. In the middle sits the West Mebon, a Hindu temple on an artificial island.

Construction probably began in the 11th century under King Suryavarman I and was completed under King Udayadityavarman II. The east dike largely reused a dike from King Yasovarman's capital, while the south dike partially buried the brick pyramid temple Ak Yum. A 713 CE stele records rice fields offered to Queen Jayadevi.

The baray's Khmer name Baray Teuk Thla means "Clear Water Reservoir." The West Mebon temple on its central artificial island once held a bronze reclining Vishnu, now displayed at the National Museum. Local residents still swim and take boat rides on the water.

Visit during the season when water levels are sufficient for boat access to the temple ruins on the central island. The southern shore serves as the main departure point where you can arrange transportation to reach the site.

The baray's western floor was once dry land: archaeologists found wall bases, steps and pottery shards there, and a 713 CE stele records rice fields offered to Queen Jayadevi. The south dike partly buried the brick pyramid temple Ak Yum, while the east dike reuses a section of the dike around King Yasovarman's earlier capital.