The treasuries of the sanctuary of Olympia are located at the foot of the Kronios hill in an area used for worship since Prehistoric times. They stand on a purpose-built terrace which extends from the Spring to the stadium, and date from the seventh to the mid-fifth centuries BC. A poros staircase connecting the terrace with the Altis below was constructed in the fourth century BC. Later a substantial buttressed retaining wall which defines the north limit of the sacred enclosure, was raised behind the treasuries at the foot of the Kronios hill. The treasuries were small temple-shaped buildings erected by various Greek cities for storing their precious offerings to Zeus. Pausanias describes some of these precious votive objects and mentions ten treasuries, namely those of Sikyon, Syracuse, Epidamnos, Byzantium, Sybaris, Cyrene, Selinus, Metapontum, Megara and Gela. However, the foundations of twelve treasuries were uncovered during excavation and only five of theses are identified with certainty (treasuries of Sikyon, Selinus, Metapontus, Megara and Gela). Most of the treasuries were dedicated by Greek cities in Italy, indicating the close ties between the sanctuary and the West.
These simple buildings consist of a single chamber and a distyle portico in antis facing south towards the sanctuary. The treasury of Gela to the far east is the only one with a hexastyle portico. The first treasury to the west, which measures 12.46 x 7.30 metres, was dedicated by Myron of Sikyon. The last four were dedicated by the people of Selinus, Metapontum, Megara and Gela. The remains of two small buildings identified as the sanctuaries of Eileithyia and of Aphrodite Ourania lie to the west of the treasuries. The eighth building from the west was probably an altar to Gaia. Excavation of the treasuries yielded a great number of terracotta architectural members with striking painted decoration, and fragments of terracotta groups - including a Satyr and Meanad, and the head of a sphinx, these latter probably from acroteria. Several of these terracottas are displayed in the Olympia Archaeological Museum, and so is the pediment of the treasury of Megara, which has a depiction of the Gigantomachy.
The monuments have been conserved.