The temple of Artemis Orthasia, protector of small children, stands in the small valley of Kotilon, at an altitude of 1230 metres, on the highest peak of Mt. Kotilion, north-east of the temple of Apollo Epikourios. The temple was erected in the Archaic period along with another temple dedicated to Aphrodite, possibly by poor Phigaleians from Bassae, which accounts for the poor construction technique. The finds from this area (bronze mirrors, terracotta female busts and the bones of sacrificial animals) indicate that both temples were used throughout the Archaic and Classical periods and were abandoned in the third century BC.

The larger temple of Artemis stands to the south of the temple of Aphrodite. It has a cella and pronaos, and its walls were built of roughly cut stone bonded with clay. There are no traces of columns or sculptural decoration. Like the temple of Apollo, it is orientated north-south instead of the usual east-west of ancient temples, possibly due to a local Arcadian tradition. North of the temple is a low limestone pedestal, which may have supported a cult statue. An emancipation inscription engraved on a bronze plaque found at the temple's southeast corner, mentions the worship of Artemis Orthasia, Apollo Vassitas and Pan Sinois.

The temple was explored in 1902-3 by P. Kavvadias and K. Kourouniotis, then Ephor of antiquities, who identified the monument on the basis of Pausanias's description (8, 41, 10).