KAIKOS (Caicus) was a river-god of Teuthrania in southern Mysia, Anatolia (modern Turkey).
The headwaters of the River Kaikos were located in the Temnos Mountains and it entered the Aegean Sea near the town of Pitane on the Mysian border with Lydia. The most important neighbouring rivers were the Satnioeis to the north-west and Hermos to the south.
OKYRHOE (Pseudo-Plutarch On Rivers 21)
CAICUS (Kaïkos), two mythical personages, one a son of Oceanus and Tethys (Hesiod, Theog. 343), and the other a son of Hermes and Ocyrrhoë, who threw himself into the river Astraeus, henceforth called Caicus. (Plut. de Fluv. 21.)
Source: Dictionary of Greek and Roman Biography and Mythology.
CLASSICAL LITERATURE QUOTES
Hesiod, Theogony 337 ff (trans. Evelyn-White) (Greek epic C8th or 7th B.C.) :
"Tethys bore to Okeanos (Oceanus) the swirling Potamoi (Rivers) . . . Simoeis, who is godlike, Hermos (Hermus) and Peneios (Peneus), and Kaikos (Caicus) strongly flowing [in a list of rivers]."
Aeschylus, Fragment 67 Mysians (from Strabo, Geography 8. 1. 70) (trans. Smyth) (Greek tragedy C5th B.C.) :
"Hail, Kaikos (Caicus) and ye streams of Mysia!"
Aeschylus, Fragment 68 Mysians (from Photius, Lexicon 344) :
"Hail, thou first priest of Kaikos' (Caicus') stream, by thy healing prayers mayest thou preserve thy lords!"
- Hesiod, Theogony - Greek Epic C8th - 7th B.C.
- Aeschylus, Fragments - Greek Tragedy C5th B.C.
Other references not currently quoted here: Pseudo-Plutarch On Rivers 21.