Prasat Ak Yum is located Southern end of the West Baray, built in the 7th to 9th century and dedicated to Hindu.
AkYum is a recently cleared site and is of great historical importance because it is the earliest site in the area. Dating from the seventh century it belongs to the pre-Angkor period. Inscriptions found on pillars give the dates of AD 609, 704 and 1001 for Prasat Ak Yum. Evidence of a linga and some sacred depository has also been found.
During the construction of the West Baray around the 11th century this site was partially buried by the south levee of the baray.