[1][2] Little is known about Onchestos and only two literary sources (Plutarch in Quaestiones Graecae and Pausanias in Description of Greece) gave information about him.
In these accounts, he was described as the Boeotian son of Poseidon[3] and father of Megareus and Abrota, wife of King Nisos.
[citation needed] When Nisus, from whom Nisaea acquired its name, was king, he took a wife from Boeotia, Habrotê, daughter of Onchestus, the sister of Megareus, a woman who, as it appears, was both exceptionally intelligent and remarkably discreet.Distant from this mountain fifteen stades are the ruins of the city Onchestus.
In my day there remained a temple and image of Onchestian Poseidon, and the grove which Homer too praised.In ancient times the city of Onchestos was famous for its sanctuary of Poseidon and is mentioned in the famous "Catalogue of Ships" in Homer's Iliad where it is referred to as the god's "bright grove.
"[5] In the Homeric Hymns to Apollo the grove is also mentioned:[6] And further still you went, O far-shooting Apollo, and came to Onchestus, Poseidon's bright grove: there the new-broken colt distressed with drawing the trim chariot gets spirit again, and the skilled driver springs from his car and goes on his way.