Its ancient name is " Gadara ". It was one of the important cities in Jordan during the Greco-Roman period. It is situated on a hilltop north-west of Irbid. In the Roman period it became a city of the Decapolis. During the period of Emperor Trajan it reached its golden age and most of its buildings date back to this period.

Strabo, the Roman geographer, mentioned it as a city famous for its hot springs. The general plan of Um Qeis follows the pattern of Greek and Roman cities. It contains theatres, colonnaded streets, baths, churches and tombs. A famous Greek inscription is engraved on a basalt lintel which reads : " To you I say, Passer-by : As you are, I was; as I am; you will be; use life as a mortal ".