Amphilochian Argos was the most important city in Amphilochia in Ancient Greece, situated on the Ambracian Gulf.
It was, according to Greek mythology, founded by Amphilochus after the Trojan War. According to Thucydides (2.68), Amphilochus, not caring for the situation in Argos, founded "Amphilochian Argos and the whole region of Amphilochia".
Argos was later colonised by its Ambraciot neighbours at the invitation of the Amphilochian Argives. According to Thucydides, "at that time [the inhabitants of Amphilochian Argos] became hellenized, regarding their present language, by their Ambraciot fellow-settlers." These Ambraciots later drove out the Amphilochian inhabitants of the city. The Amphilochians allied themselves with the Acarnanians and also with the Athenians, who despatched thirty ships under Phormio that successfully drove the Ambraciots out of Argos.
It took an active part on the Athenian side during the Peloponnesian War in alliance with its neighbours the Acarnanians against the Ambraciots and Leucadians, who were supported by their mother city, Corinth, and the Peloponnesian League.