Gerrha

The city is 200 stadia [c.32 km] distant from the sea; and the Gerrhaeans traffic by land, for the most part, in the Arabian merchandise and aromatics.

Gerrhean incense is reported as an ingredient in Greek poison and it was also an essential item on some discovered shopping lists.

Robert Hoyland has suggested that a likely factor in this expedition was for Antiochus to use a show of force to get the Gerrhaeans to direct more of their trade through his territory.

Hagar (Gerrha) is not to be confused with the west Arabian Al-Hijr (al-Hijrah, ancient Hegra), the present-day Mada'in Saleh or al-Ula near the Red Sea.

[9][10] The researcher Abdulkhaliq Al Janbi argued in his book that Gerrha was most likely the ancient city of Hajar, located in modern-day Al-Ahsa, Saudi Arabia.

[11] Al-Janbi's theory is the most widely accepted one by modern scholars, although there are some difficulties with this argument, given that Al-Ahsa is 60 km inland and thus less likely to be the starting point for a trader's route, making a location within the archipelago of islands comprising the modern Kingdom of Bahrain, particularly the main island of Bahrain itself, another possibility.