The Wikipedia mentions: “Umm Qais (Arabic: أم قيس‎, also transliterated as Umm Qays) is a town in northern Jordan near the site of the ancient town of Gadara. It is situated in the extreme north-west of the country, where the borders of Jordan, Israel and Syria meet, perched on a hilltop (378 metres above sea level), overlooking the sea of Tiberias, the Golan heights and the Yarmuk gorge. Umm Qais is in Jordan's Irbid Governorate and belongs to the Bani Kinanah Department.
The Hellenistic-Roman town of Gadara (Hebrew: גדרה‎, gad´a-ra or גדר, ga-der; Greek: Γάδαρα Gádara) was also sometimes called Antiochia or Antiochia Semiramis (Ancient Greek: Ἀντιόχεια Σεμίραμις) or Seleucia.“
I found the ancient town surprisingly large, with the main sights well excavated, but probably a lot of finds still in the ground. It was much more extensive than expected. I found a very good site with information (that I quote from).

For a clear view of the area covered use the map view.. Location of sub-galleries: see there.