Beit Ras, a modern village just north of Irbid, sits on top of the ancient Decapolis city of Capitolias. Unlike the dramatic ruins of Umm Qais or Jerash, Capitolias has been built over by a living town, but archaeological excavations have turned up substantial remains: a theatre, a colonnaded street, a nymphaeum, and exceptionally fine mosaic floors.
The site is not formally open to visitors in the usual sense, but the local authorities and the Jordan Department of Antiquities permit access to the excavation areas. If you have a particular interest in Roman provincial cities or are writing about Jordan's archaeological heritage, it is worth making contact in advance. The site is easy to combine with a visit to Irbid's Museum of Jordanian Heritage, where many of the finds are displayed.