The Amazons Myth, is mostly just this; a legend about the "other" living beyond the realm of the civilized world. Amazons thus have the same mythological status as sea-monsters, dog-headed people, hyperborean giants and other creatures that ancient peoples placed "at the edges of the map".

Is there a grain of truth in it? There might be, albeit very, very tiny. The closest candidates for legendary "warrior women", were ladies of ancient Scythian and Sarmatian origin. Archeological finds show graves of women buried with weapons and combat clothes, which would suggest they might have been warrioresses. About 20-25% of those women were buried with bows, which might give some credibility to the myth of Amazons being superb archers.

NOW, whether these women were truely warrioresses (huntresses?) or maybe the burial was somehow symbolic in nature is all guesswork. It is however a fact that similar "shieldmaiden graves" were found throughout Asia and Europe, and up to the Viking Age, among various nomad-Asian, Germanic tribes and among Vikings. So at the very least we have a strong trend of warrior-women being a thing in many cultures, for at least 2 millenia.

Was there ever a female-only or female-dominated (matriarchal or otherwise) society? As far as we know: no. We must take into account however, that many nomadic or semi-nomadic cultures would have de-facto female-ruled or female-oriented society while men were away for war or following the herds for months at a time. These women would be more than likely capable of defending themselves and their families out of necessity. An encounter with such women might, or might not, be the origin of the myth.

Wilcott: Greek Attitudes towards Women: The Mythological Evidence

Lyn Webster-Wilde: Material for the study of women and gender in the ancient world.