Cissia(Ancient Greek: Κισσία, Kissia) was a very fertile district of Susiana in the Persian Empire, on the Choaspes.
Once the Ionian Revolt was finally crushed by the Persian victory at the Battle of Lade, Darius began to plan to subjugate Greece.
In 490 BC, he sent a naval task force under Datis and Artaphernes across the Aegean to subjugate the Cyclades, and then to make punitive attacks on Athens and Eretria.
Reaching Euboea in mid-summer after a successful campaign in the Aegean, the Persians proceeded to put Eretria under siege.
Darius the Great, contrary to Eretrian expectations, treated them kindly, and gave them a village in the country of Cissia for their habitation, which was but a day's journey from Susa, where Apollonius of Tyana found some of their descendants 600 years afterwards.