Onceium or Onkeion (Ancient Greek: Ὄγκειον) was a village in ancient Arcadia upon the river Ladon, near Thelpusa, and containing a temple of Demeter Erinnys.
[1][2] The Ladon, after leaving this temple, passed that of Apollo Oncaeates on the left, and that of the boy Asclepius on the right.
[3] The name is derived by Pausanias from Oncus, a son of Apollo, who reigned at this place.
Other writers mention a small town Oncae (Ὄγκαι) in Arcadia, which may be the same as Onceium.
This article about a location in ancient Arcadia is a stub.