This sanctuary consisted of a rectangular enclosure (60 x 50 metres), which was entered on the east side through a rectangular propylaea in antis (built in the fifth century BC) fronted by a short staircase and a circular structure. Outside of the enclosure, the propylaea is flanked by the remains of a long portico ("stoa") with seats for the pilgrims, who left evidence of themselves in the form of various altars and votives. Inside the enclosure, there was the large altar (16.3 metres long x 3.15 metres wide) in the centre, on top of a pile of ashes from the bones and other parts of the sacrifices. It had an extension to the southwest, while the remains of an earlier archaic altar are visible near the northwest extremity and there is a square pit on the temple side of the altar. Between the altar and the temple there is a canal carved in the rock which, comes from the north, through the whole area, carrying water to the sanctuary from a nearby spring. Just past the canal is the Temple of Demeter itself in the form of a "megaron" (20.4 x 9.52 metres), lacking a crepidoma or columns, but equipped with a pronaos, naos and adyton with a niche in the back. A rectangular service room is attached to the north side of the pronaos. The megaron had an earlier phase recognisable only at the foundation level. South of the temple there is a square structure and a rectangular structure of unclear function. North of the temple, another structure from a later period with two rooms opening onto the inside and outside of the temenos forms a secondary entrance to the enclosure. The south wall of the enclosure was periodically reinforced to fight the subsidence of the hillside.