Elymais was an ancient kingdom or autonomous state that existed approximately between the 2nd century BC and the beginning of the 3rd century AD. It was located in the region that today corresponds to southwestern Iran, between the Zagros and Persis mountains (present-day Fars region), covering areas near the ancient city of Susa. This territory was the successor to the ancient kingdom of Elam and was under the rule and vassalage of the Parthian Empire.

The inhabitants of Elymais, known as the Elymians, were renowned for their skillful archery and for maintaining their own cultural identity during the period under Parthian and later Sassanian influence. Elymais had its own numismatic production and local monarchs, reflecting a degree of autonomy within a larger imperial framework.

In short, Elymais was a local Persian kingdom located west of the Zagros Mountains, historically associated with Elam and linked to the Parthian Empire, with independent or semi-independent existence until the beginning of the 3rd century AD.

Sources:
Wikipedia
Numist