The Alenon River is where the Kelpies come ashore, which is said to be a stunning sight. It is located in the Gloaming Valley and near Rimeshire, where the Dizznee family lives. It connects to the ocean. It was first mentioned in Lodestar.
In Lodestar, Biana asked Juline if they are near where the Kelpies come ashore, saying that Della told her about it. Juline says that they are on the other side of the mountain, but that she could take Biana for a day trip some time. It has not been mentioned since, but, since Rimeshire is snowy and cold, it can be inferred that the Alenon River has the same climate.