In Greek mythology, Ladon is the Arcadian river-god — son of Oceanus and Tethys in Hesiod — whose stream is a major tributary of the Alpheus in the Peloponnese. He is father of Metope (wife of Asopus and mother of Aegina) and, in Arcadian lore, of the naiad Daphne who flees Apollo. Distinct from Ladon the serpent who guarded the Hesperides' apples (atlas id ladon).
Adapted from Wikipedia, "Ladon (river)" · CC BY-SA 4.0
I.River and genealogy
Hesiod lists Ladon among the rivers born to Oceanus and Tethys. By Stymphalis (or in Apollodorus without that detail) he fathers Metope, who marries Asopus and bears the Asopid nymphs, including Aegina — so Ladon stands as a grandfather of Aeacus and the Aeacid house.
Pausanias describes the living stream: springs in Cleitor's territory, course past sanctuaries of Eleusinian Demeter, and the town Thelpusa named for a daughter of Ladon. He also records an Arcadian Daphne, daughter of Ladon, as Apollo's beloved — a local rival to Ovid's Thessalian Daphne of the Peneus.
II.Homonym and cult lore
Apollonius and later poets give the name Ladon to the hundred-headed dragon of the Hesperides; that creature is a separate atlas node (ladon). Demeter's washing in the Ladon after Poseidon's assault was remembered in an Arcadian proverb about cooling anger.
Other children attached to the river include the naiads Telphusa and, in Ovid's Pan–Syrinx chain, Syrinx. The atlas id ladon-river locks the Arcadian water-god against the dragon.