The ancient city of Arjan is situated at a distance of 10 km. north of Behbahan. Today, only hillocks from this city have remained which belong to the Sassanide period. Previousely, this city used to have six gates which were named as, Ahvaz, Ray Shahr, Maidan, Kialin, Shiraz and Eazeh. The Hoomeh or Homayoon hill is the largest one in Arjan city.
The residential palace of Shah that today only the ruins of which have been remained and is reputed as “Saraye Malek”, is located to the southeast of Arjan city. Due to an unknown condition this city was demolished, and the current Behbahan city has been formed at its vicinity.