[4] Today the site is found east of the modern town Markopoulo Oropou in the Oropos municipality of Attica, Greece.

The sanctuary is located 37.2 km NNE of Athens[5] at a sacred spring; it contained a temple of Amphiaraos (with an acrolithic cult statue), as well as a theater, stoa, and associated structures.

Herodotus relates that the oracular response of this shrine was one of only two correct answers to the test put to them all by the Lydian king Croesus.

[10] At the Temple of Amphiaraos, the site is about 154 m in elevation, with a gentle slope to the northeast, as it fills the northwest bank of a small ravine between two hills.

The early 4th-century BCE temple of Amphiaraos was of an unusual Doric hexastyle in antis plan: i.e. it had six columns across the front façade between small projecting walls.

Alongside the second pair of columns back from the pronaos there was a base for the acrolithic cult statue of Amphiaraos of which one arm remains in situ.

On axis with the center line of the temple, and about 10.5 m (34 ft) northeast, are the remains of the altar divided into sections with inscriptions to a number of gods and heroes.

To the northeast of the temple was a line of dedications of statuary, of which the bases (illustration, right) have largely survived; the avenue stretched for around 70 m (230 ft) along the road into the sanctuary.

On the southeast side of the streambed opposite the sacred spring are the remains of an unusually well-preserved klepsydra, or water clock, dating to the 4th century B.C.

Outside, a flight of steps leads down to a narrow service area that allows access to the lower wall of the reservoir, where a small bronze outflow valve is inserted into a hemispherical depression just above the bottom of the tank on the northwest side.