Like the Bath of Varius, the State Agora was renovated multiple times during its history. The first agora on this site was built in the 6th century B.C. in Hellenistic style. During excavation that agora was found buried approximately 2 meters below the present Agora. The current structure would have been built in the Roman Period in the first century B.C. along with a square temple. The temple was demolished during the reign of Augustus and never rebuilt because of its connections with Egypt. The Agora was reconstructed in the 3rd century during the reign of Caracalla (211-217 A.D.)  The final renovations were done by Emperor Theodusius (between 379-395 A.D.)

This agora would have been used as a public area and a meeting place for governmental discussions. Thee sides were bordered by Stoas, an architectural structure that would provide shelter from intense sun or rain. A water reservoir at the corner of the Agora would have been supplied by the Pollio Aqueduct, the remains of which can still be seen 5 kilometers away. In the very center of the Agora was a temple dedicated to the Egyptian goddess Isis that would have served as the chamber where all decision would have been voted on. The pink granite columns still remain of the temple, proving a relationship once existed between Egypt and Ephesus since there are no pink granite quarries in Anatolia.

Excavations around the State Agora unearthed a large number of graves dating back to the 6th-7th centuries BC and an archaic terracotta sarcophagus. Near the area, about 3m below the surface, they also discovered a road surrounding the Panayir Mountain.  This has lead archaeologists to believe the northeast side of the State Agora must have been used as the Necropolis of Ephesus during the archaic period. One of these tombs is currently on display in the Ephesus museum.